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Custom High Tech Crayfish Tank

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I have wanted to keep a crayfish since I first saw them in my local fish store over 15 years ago. As soon as I saw one, I was like... WHAT IS THAT?

It didn't help that many fish stores where I live label them as 'lobsters'. Buying one of these guys on an impulse would probably be a terrible idea because they are not friendly tankmates. Plus they do crazy things in a tank like dig giant holes, trenches, move around hardscape, nip fingers and escape anything that doesn't have a good (and heavy) lid. They also eat plants, eat fish, eat snails, eat shrimp, eat anything they can catch.

Soooo a specialized critter.

But I still wanted one!

Since they are such a royal pain, I've never had a tank to put them in. Until now. Recently I had a saltwater build fail to get off the ground. That sucked... a lot. But it provides an opportunity to reuse that tank for something else. And that something is going to be a crayfish!

I am reasonably sure I want what is commonly called an Electric Blue Crayfish (Procambarus alleni). This is a US Native from Florida. I love US Natives for a few reasons so that's a big plus in my book. They are also very easy to breed so getting one captive bred won't be a problem. If I go that route they will look a bit like this fellow right here (not my picture):



There is also the possibility of getting a different kind of crayfish... what kind? Not sure yet. There is a reasonably healthy online community dedicated to crayfish and the USA apparently has a LOT of cool crayfish species. I mean... until recently I've seen only a few crayfish species I know are from the USA. There's the electric blue crayfish, plus a red variety out of Louisiana area called a Red Swamp Crayfish (Procambarus clarkii). And of course the dwarf variety known as a CPO or Orange Mexican Crayfish (Cambarellus patzcuarensis). Then local to me in streams I've seen some brownish ones that are likely Devil Or Common Crayfish (Cambarus diogenes or Cambarus bartonii bartonii respectively) That's about all I knew about. Apparently that's just the tip of rather large and diverse crayfish iceberg.

So I put the word out that I'm interested in captive bred blue native species and we will see if I get any hits on it.

Meanwhile... the tank!

The tank is a weird shape. It's 24 inches x 18 inches x 24 inches tall. It is drilled with a bean animal overflow and two 3/4" returns. Each return has it's own pump in the sump. I also have a UV Sterilizer and a Rex Griggs style CO2 reactor. I currently am using a Red Sea Fleece Roller in the sump but I will likely take that off and sell it and replace it with some foam.

The setup for the tank will basically be a very tall (relatively speaking) hardscape with a cave in the bottom. The cave is for the crayfish, it is not an optional additional either. Crayfish need a place they can molt in and if they can't find one they will try to make one. This is one reason so many people have trouble with them in their tanks. They don't provide good hides and the crayfish are driven to try and dig their own hide and end up destroying a lot of stuff in the process. Or so I've been told.

I am also going to try to grow plants in this tank. Now this one is a bit unorthodox for a crayfish tank. Crayfish eat plants. And even when they don't eat them, they have a tendency to dig them up, cut them up, and generally muck them up. So growing plants is not the norm for a crayfish tank.

I'm going to give it a real go anyway for all the normal reasons we grow plants. BUT I am also going to try to be smart about it. I am going to stick to either really hardy plants or really fast growing ones.

To that end the primary plant in the tank will be Vallisneria Torta. After that I will try a few varieties of anubias, some monte carlo, Hygrophila Pinnatifida, Java Moss, and a plant called Homalomena Insignis which is new to me but the description sounded like a cross between anubias and an amazon sword (not really but that's what it sounded like). All of these were ordered online and should arrive later this week.

My plan is to try a bunch of plants and see what sticks!

The next step then is the hardscape. I cleaned up the tank best I could from my saltwater adventure including removing all the sand. I also filled and emptied the tank a few times to get rid of as much saltwater residue as possible in the plumbing. After that I began playing around with possible designs.

The main feature was always going to be the cave, so the first thing I did was try to construct that.



It honestly came together a lot quicker then I thought it would. So I kept at it, adding in more rock and moving the wood around.



Eventually I ended up with this:



At this point I was ready to start adding sand.

Now a word about my cave. Everything in the tank right now is rock or wood. My plan for the cave was to use small stones to fill in cracks to keep the sand out of the cave. When it was dry, that worked fine.



Unfortionately as soon as I filled the tank with water, the cave filled in with sand from above. Nothing I could do would keep that from happening. So I drained the tank, scraped aside the sand, removed the rock that made up the roof of the cave.





Then I used strips of filter foam I cut for the job and stuffed them around the edges where the sand was getting in, then reassembled the cave.



This time the cave remained a cave, huzzah!

Also somewhere in there I added some small stones/fine aquarium gravel and safe-t-sorb to the sand to give it a more natural and less unform appearance.

I was not entirely happy with it like that. I decided I really wanted the back left corner to be raised up higher so you could see it even when looking at the tank from in front and low down. I added a couple more rocks and more sand. After a night running the tank to clear up the water here is how it looks today:



Overall I am really happy with how the hardscape turned out.

The plan will be going forward to plant the Vallisneria in the back of the tank. Then all other plants to go ontop of the cave/wood with maybe 1 or 2 anubias plants tied to a rock down in front. But otherwise to leave the front of the tank clear of plants so my resident bulldozer can have some space to do his thing. Ideally I will let the plants growout for a month or so before adding my crayfish. So we are still a while away from getting my decapod.

That leads me to tank mates.... and whether I can even have any. Online I see a WIDE variety of responses to this question. Some people say crayfish will murder everything, others say they have a lot of luck with certain fish species etc. So it's not entirely straight forward. I have noticed that small fish species are less likely to be caught and eaten then larger fish species. Some people have had luck with shrimp as well.

To that end I will try some fast moving tiny fish species in this tank. Honestly what I am most excited for is trying some killifish in this tank. I have always wanted to keep some of the more interesting varieties but all my tanks are open topped and killifish generally are fantastic jumpers, so it's never been an option. Given that this tank will need a lid, I think it might be a great opportunity to get one. Assuming of course the crayfish doesn't murder them all to death......... :p

And that brings me up to current. Next time I will hopefully start some plantings!
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Discussion Starter · #3 ·
Looks great, I always liked the look of those "blue lobsters" too.
Way back before the interent was a thing I kept wild common crayfish that I had caught out of a pond in an aquarium and they would dig like crazy.
They ate or destroyed for fun any plants I ever put in there except duckweed, again just random things I collected from local stream, ponds or lake that I thought looked cool.
You might want to think about using the super glue and cotton trick to make that cave area as one solid piece, that way if it decides to rescape for you it won't have fatal consequences.
Thank you!

I definitely worried a bit about the cave when setting this up. My main concern with the filter foam is that the crayfish will pull it out from inside the cave and then the darn cave will fill with sand requiring me to redo this tank again, but this time with plants and crayfish already on location. I took pains to make that harder/impossible, but its still a worry for me. I'm not too worried about the crayfish excavating the rocks mostly because of how big they are. The two walls of the cave are BIG rocks - about 20lbs each. The roof is smaller, about 10 lbs. BUT there is another 10 lb rock on top of the first one. I also put the whole thing together without it relying on sand to hold it up. Meaning the crayfish can't dig under it and destabilize it that way. So I think I'm safe regarding him collapsing the structure.

I've used the superglue cottonball tricks before with hardscape but I truly hate doing it because then the pieces used are essentially ruined in any other scape due to all the superglue marks on them. These days I try to rely on mass, and clever placement to hold things together. Hopefully that's enough here.

One of my bigger concerns about the crayfish-plant situation is the fellow just destroying the plants for giggles. At least one person who is currently keeping a planted tank with crayfish that I talked to on facebook opined that as crayfish get older they tend to chill out more and not be as interested in eating or destroying plants. Sooo.... we shall see if I can make it happen. If I can't then I'll likely end up keeping this tank as a hardscape only one. But I definitely want to give it a very solid try with plants involved.
 

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Discussion Starter · #7 ·
Update!

Tank is still cycling, and this despite the fact that I dropped in several bags of ceramic media from established filters (kept there specifically for this purpose of seeding a new tank). This just further solidifies in my mind that biomedia in a filter is truly pretty worthless in a planted tank. If my media had a good sized bacteria colony it should have handled the 1ppm of ammonia I added to the tank relatively quickly (as opposed to what I am experiencing; no change after several days). The fact that it hasn't processed the ammonia yet means there must not have been a very large bacterial colony in the biomedia. Probably because I don't let waste build up and I have a lot of surface area in the tank itself.

Anyway.......

The true reason for this update is that I got my plants in!

Specifically I added to the tank: Micranthemum 'Monte Carlo', Anubias Congensis Mini, Homalomena Insignis, Vallisneria Torta, Hygrophila Pinnatifida, and Java Moss. In addition to the plants I got in from online, I moved over several anubias plants from my high tech newt tank which I think were anubias nana. After planting here is how things look now:



I also noticed that my co2 was empty a couple of days ago so this morning I got that filled. That plus the doser hooked up (using pps-pro on this tank) means I have a fully operational system! or I should at least time will tell if there are any glaring problems :p

Next up I need to make a lid for this tank. Once it cycles I will also move in some ricefish to maintain the cycle and probably live in this tank (hopefully forever).
 

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Discussion Starter · #9 ·
Small Update:

Tank is now cycled. The ammonia finally reduced to zero as did nitrite. I did a big water change and added some of my white ricefish that have otherwise been just sitting in my quarantine tank for months now.



Picture of the crayfish and newt tank sitting next to each other:



In other news I am seriously contemplating making the fish in this tank just killifish. I have long wanted to keep killifish but they are generally all jumpers (ricefish being one of the few (only?) exceptions. To that end I bought from amazon some annual killifish eggs which promptly did not hatch (as near as I can tell). So I'll need to try again. Only problem being that it seems most of the people selling killifish eggs are recently collected ones and they all need to be incubated for 4 months before hatching. So if I got some I could potentially be able to introduce juveniles into the tank sometime around late winter to early spring 2023..... not exactly what I was looking for :p

Sooo... it's a work in progress.

Next up is making the lid which will allow for killifish and crayfish keeping to actually work.
 

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Discussion Starter · #10 ·
Update!

Top of the morning to you.. Or some other top related pun.

Time to make a top!

I poked around my scrap wood pile to see what I have available. I wanted mahogany but sadly the only board I have left is not quite wide enough to get all the pieces out of it I will need. Of the wood I had left, there was cherry, red oak, and poplar. I decided against the cherry and poplar based on it being a softer wood and I suspected might be prone to warp given the high humidity/water exposure of this application. That left just the red oak and so that was what I used. I'm glad I decided on it as well since I definitely messed up a 45 degree angle cut and needed a new piece which would have been annoying with the cherry since I don't have a lot of it in the right sizes. On the other hand I got a pretty good pile of oak.

I milled the stock square then cut a 1/8" kerf with the table saw .5 inches from one edge. This will be where the screen/spline goes. On the opposite side I used my routing table to create a rabbit 3/8" deep and a little more then .5 inches wide.

Using my miter gauge I put 45 degree angle cuts on both ends. I also went back and forth to the tank itself multiple times to make sure I had the right sizing. Here is what the pieces looked like:



After that I just needed a strap clamp and some titebond 3 to glue it up.





This is the third top like this I have made since both of my newt tanks have similar tops. It is the first one that will have a screen in the middle, but otherwise it's the same kind of construction as the other two. I am definitely getting better at them as I go though. The miters on this one are in fact really tight, which will save me both time and energy down the line.

After it dries I will sand it and then probably apply a stain and finish. Once that dries I will add the screen and then tada, I will be ready for some killifish which I am increasingly certain will be ones I buy as hatched fish rather then as eggs.
 

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Discussion Starter · #12 ·
Oh man I love crayfish. Ive never had one of those but the creeks around here in north AL have always been full of other varieties. Ive kept dozens of them in various set ups over the years

Yes voracious predators. They arent gonna chase anything down but any fish that swims close enough to get grabbed is toast. Ive seen them snatch comet feeders as big as they were right out of mid-water, sit there and hold it taking casual bites like it was a hamburger in the park til there's nothing left to hold onto, fish squirming for dear life the whole time...pretty brutal. So know that before you put any fish in there you dont want to get eaten. Stick with top dwellers only

Another thing, it's not gonna just move into that nice little hole you built for it. Nope. Its gonna find some other rock like down in front right, or up on the left under the one that's not even flat. It'll pick a spot somewhere and rearrange pounds of sand while it makes its own burrow. Idk how big yours will be to start with but at two or three inches they can literally move 6" of substrate...somewhere else, lol. So get ready to have all that rearranged eventually

Great journal btw, both those tanks look sweet! I look forward to seeing the crayfish chronicles
There are some really cool species of crayfish in Alabama! I'm on a facebook group that has Chris Lukhaup aka The Shrimp King as an admin. I think he has the craziest life of anyone in the aquarium community. Basically travels the world taking pictures of inverts. Anyway, he has been posting pictures of his last trip to the USA and recently posted this guy from Alabama:



There have been some other people posting Alabama crayfish as well. It seems crayfish have a LOT of color variation between species which seems to be way more dramatic then many other of our north american inverts.

Despite all that the whole keeping community seems to be limited to only a handful of species (at best). It's kind of wild that folks haven't started keeping some of the more colorful or unique species that live right in our own backyards. I think the demand is just not great enough to make it work since they tend to be species specific setups.

I've definitely noticed people reporting their crayfish eating fish, especially fish that are either slow moving or larger. It seems (purely from my own reading, clearly have no experience) that the larger the fish the more likely it is to get eaten. I'm hoping a small fish that lives in the top of the aquarium (hence my desire for killifish) will be able to live without being dinner.

Yeah, I know they can be little bulldozers in an aquarium, soooo.... we shall see :p I'm hopeful the vallisneria will grow deep enough roots to discourage moving all the sand from the back to the front for instance but that's kind of all I got for planning purposes ;)
 

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Discussion Starter · #13 ·
Small Update:

The top is complete!

I put on some minwax red mahogany stain and a coat of tung oil. Putting red mahogany stain on a piece of red oak in no way makes it look like mahogany. But we work with what we have :p

I also got the screen installed. This latter took 3 tries before it went in right. The first 2 failed because my spline was .125 inches in diameter or the same size nominally as my kerf. That turned out not to produce the best hold on my screen. So I went out and bought some .140 diameter spline and while harder to install, that definitely did the trick.







Next up will be finding some fish and also a period of growing the plants in before the crayfish is introduced. I'll be away on vacation for a week though so pretty much nothing is happening until I get back.
 

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Discussion Starter · #15 ·
Small Update:

It's been a little more then a month since planting. Not a lot has happened during that time but plant growth. I did add some ghost shrimp and a few cherry shrimp. I've seen folks online say they lived harmoniously with their crayfish, so I figured I would give it a go.

Here is how the tank looks today after water change:





I tentatively will begin looking to get a crayfish into this tank sometime in the next 2 to 3 weeks. This is dependent on the vallisneria in the back continuing to do well. Its only really started to take off in the last 10 or so days.
 

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Discussion Starter · #17 ·
Update!

I am back from vacation and can finally move forward with the main attraction, the crayfish!

Actually finding the little guy turned out to be more of a challenge then I thought. I just assumed I would immediately be able to get one, but it turns out that I want one of decent quality and that took a lot longer to track down. I literally visited about 10 different pet stores (local and chains) until I found what I wanted. The wait was worth it though since he (and I'm pretty sure it is a male) is pretty darn cool!

To introduce him to the tank I drip acclimated him for a couple of hours. I actually got him at a petco but he was still floating in his bag from a recent shipment when I bought him, so he never got introduced to their water. I was somewhat shocked to find that the TDS of the bag water was over 1800. I guess they transport them with salt?

Here is how he looked shortly after introduction:



He immediately roamed the tank and its easy to see how they can tear a tank apart if they have a mind to. He disturbed several plants (my monte carlo that never took off and some hydrocotyle tripartita) and that was just him walking around without trying. Neither was dug up enough that I needed to do anything to them though so we shall see what makes it and what doesn't.

Here are some more shots of him:







These are all phone pics. I need to get my real camera out and shoot him later tonight or tomorrow.

Meanwhile, I previously added some more fish to the this tank. I had wanted killifish and even bought some eggs online but sadly they never hatched. I instead shifted slightly and bought some clown killis when my local fish store had them at a good price. They are pretty hard to photograph with a phone and frankly I am hoping they color up a bit as they grow/adjust to the tank but here is how they look now:



That's all for now, going forward its all going to be about watching how the crayfish does and adjusting things as needed.
 

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Discussion Starter · #21 ·
What a great specimen!



:unsure:



Some of their wholesalers load their bags up with medication prior to shipment. It's... not my favorite thing.



If you're lucky, the cray will develop a tiny appetite for some plants like this that grow quickly. I've never found them to be too plant-hungry, though.



That really is great coloration for a cray that's new to the tank and that's just discovered its main hidey hole.



These are going to be awesome in this tank. Such an underrated fish.
Thank you! I am pretty happy with him and also with the fish. I have wanted them for a long time but they are jumpers and I've not wanted to have a full top before now.

Great looking cray.
Thank you!

What an amazing crayfish. I love the way the crayfish contrasts with the hardscape. Your custom tank lids are really nice looking, too.
Thank you! It's fun making the lids, I feel like I'm getting better each time I do one at this point :p


And now... a small update:

I got out my real camera and took some pictures:









 

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Discussion Starter · #24 ·
Small Update:

Mr. Pinch successfully molted. He hid out for a few days leading up to it and then became a bit more visible after it was done. Now he mostly sticks to his cave and a connecting cave, but I see him out and about every so often. Here is a full tank picture and the real reason for the update:

 

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Discussion Starter · #25 ·
Small Update:

The tank is cruising along. I am getting some hair algae on my plants and the hygrophila pinnatifida is getting some brown spots. The latter is making me think there is a lack of nutrients so I've been slowly upping the dosage of ferts. I started off dosing 4ml of macro and micro. I am currently dosing 7ml of each.

Meanwhile Mr. Pinch has shown some small proclivity for cutting plants which float up and gather around the overflow. Thus far its entirely manageable, but we shall see :p

Speaking of, here is the latest picture:

 

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Discussion Starter · #28 ·
Looks like he's just chillin'...

Can't remember if you mentioned it but what do you feed this guy?
I feed him some bottom feeder pellets and some food marketed as food for inverts. I also occasionally feed him live black worms since I am culturing them for my newts currently. A few times I've fed cut earth worm. He goes absolutely bonkers for the black worms. Watching him dig them out of the sand using every leg to sift them up is amazing. He is clearly designed for that specific activity.

I look at this journal way more than is healthy. Gotta fight the urge. Gotta fight the urge. Can't set up another tank.

What do the brown spots on the H. pinnatifida look like? For me it's always been a plant that needs more CO2 than I usually think I'm comfortable with. But I've mostly been growing it in our gross tap water (4 kH, 12 gH, who knows what else at any given moment) through the years. Seems to also do better for me in tanks where I position it much like you position yours - kind of above everything else. I bet it's just getting broken in and will still adjust a bit more before exploding in the tank.
Its still growing and spreading but its honestly looking worse and worse. Maybe its getting too much fertilizer? Or is my fertilizer really this low of a level?

Here is a picture from this morning when the tanks lights are still off.

 

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Discussion Starter · #30 ·
Do you know if it was emersed or submerged growth when you got it? Any time I've gotten emersed, I've usually had a majority of it melt. Only the submerged stuff has worked well for me. And part of a tissue culture I got from Petco, of all places - which, honestly, is the best success I've ever had with it. You should check online and at local Petco stores to see what's available to you.

The only special things I do with it are make sure it gets plenty of light - and it is in your tank due to its position - and plenty of potassium. I don't know the exact amount of potassium, but I usually double what I normally put in my dry fert mix. Probably 35-40ppm, if I had to guess. With more CO2 than I like to run, of course. I just don't like to use it on invert tanks. So that's why I say more than I'd like - usually running what most would consider an average CO2 concentration.

Learned the potassium thing here on the forum from an old timer a long time ago. Maybe Diana? Just tried searching for the thread but no luck yet. I think it was in a tank journal, so I'll try to dig deeper later to find it. I've also seen people have better luck when dosing leaner micros. I usually don't add them to any of my tap water tanks or shrimp tanks where I remineralize with Salty Shrimp or my own blend, so I'm not sure if that plays a role.

I'd start by trying to increase potassium to see what happens.
I'll need to buy some potassium then. I am using pps-pro on this tank from Nilocg, so the potassium is mixed in the formula with other macros.

The growth you see in the picture is the new growth since I planted it. The old growth is all gone now. It was doing much better when it was new. It started going down hill before I started remineralizing my water, but I doubt the salty shrimp I've been adding has helped it any. I've been adding enough to get my TDS to between 200-250. I also have some cuttlefish bone floating in the sump, I wonder if that could be causing my issues?
 

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Discussion Starter · #32 ·
Small Update:

I think things are going better. I bought some seachem potassium and I've been dosing it every few days (typically when I remember.... theres a reason I otherwise use a dosing pump on this tank :p) and new growth is looking better. Plus the hair algae is going away.

I added a bunch of ghost shrimp to this tank a week ago. My local fish store sells them as feeders and they basically keep them in brackish water (TDS 2500!), but I dripped acclimate them and they seem to be doing pretty good. It's hard to say if Mr. Pinch is eating them or if they are prospering as counting their numbers is essentially impossible. All I can say so far is that I haven't found any dead bodies.

Mr. Pinch is frankly becoming less shy by the day. For a while he would hide when I came into the room but he is clearly learning that I mean food and is starting to come out of his cave claws up and ready to receive anything coming his way. It helps I think that I've been feeding him blackworms or earth worms when I feed the newt tank next door. To say he goes wild for them is the understatement of the year.

In other news I have started removing all the java moss from this tank. It frankly grew too quickly and too wild for my liking. I hope to replace it with some nice fissidens.

Picture of the current situation:

 

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Discussion Starter · #34 ·
Awesome build. Love the little blue guy too. Don't know if you subscribe to Amazonas Magazine but they had an informative article a couple of years ago about crayfish. It was a German aquarist, his name escapes me right now, but he keeps lots of interesting and colorful North American species as well as different Cherax from Australia/PNG. Check it out if you get a chance.
Was it Chris Lukhaup by any chance? He has a crayfish Facebook group and occasionally comes to America just to snorkel for crayfish and shrimp in the rivers and streams here.

There are some really crazy looking crayfish that frankly SHOULD be in the hobby but just are not. Crayfish are super cool but are generally considered a specialized sub genre for the hobby. Watching this guy's behavior and how he interacts with the tank is super interesting for me in large part because he is so completely different than any other critter I have kept before. A weird mix of hyper aggressive and frightfully shy when surprised.

You reminded me I really needed to subscribe to that magazine, I went ahead and gifted myself a subscription :)
 

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Discussion Starter · #38 ·
My favorite crawfish is Cajun style. Haha.
They do come in so many colors, pretty wild,

how is the crawfish doing with the fish?
I'm pretty sure he has gotten a few of the rice fish (as opposed to them dying from other causes) but now that the clown killis have settled in he hasn't gotten any of those.
 

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Discussion Starter · #44 ·
Amazonas Magazine September/October 2020

Interview — A visit with crayfish breeder Markus Güsgen by Ute Dederer and Friedrich Bitter

Sorry it took me awhile to find the article. They do sell their back issues as well.
Nice! I just got my first issue in the mail. I'll have to look up that back issue. Considering that I spend hours a day reading about fish online, I'm surprised it took me this long to get a subscription.
 
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