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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!