[Roboto]

Hi There - I'm curious what methods/process other people have for dealing with a problem tank.

I have 5 tanks, 4 of which are very healthy.
The problem tank I have seems to slowly make some of my fish sick, mainly the bottom dwellers. The cories and bolivian rams I've had in there lose appetite and get pretty lethargic and eventually wither away.

I've completely changed out the substrate to match my other tanks which is eco-complete on top of flourite black sand with 40-50% exposed black sand for sand sifters. I had a harlequin rasbora jump out yesterday and some cories that I recently added don't seem happy so I've been moving them back to my quarantine tank.

I have been mostly successful with rasboras (added 8 of them 8 months ago and they've all done well except for the jumper yesterday and one has had swim bladder problems for months). The rasboras are often seen spawning. An albino pleco has thrived since she was added. Amano shrimps are doing great. And of course some danios I've had in there had no problems but I've moved them because they hog all the food so now they have their own tank.

I'm at the point of moving all livestock out since I have capacity in other tanks to safely hold everyone.

My question is, how much of a nuclear approach do I take in resetting up this tank?
Here are my givens:
- Completely clean filters and use new filter media in conjunction with media from my other healthy tanks.
- Replace all substrate. This is sad because 3 weeks ago is when I tore this tank down and replaced the substrate thinking it was causing the majority of the problems. Can I soak this in something and reuse it?

My questions start getting murky when considering driftwood, plants and rocks.
Something is just not right in this tank.

My only last consideration before a complete tear down is that I've never run any carbon on this tank. Should I consider doing that before going nuclear?

Thanks for any help and tips from the more experienced fish keepers here.

 

[gjcarew]

Do you have a picture of the tank?

Sent from my Pixel 3 using Tapatalk

 

[PlantedRich]

If you have a combo of sub that you favor and it works on other tanks, I would not consider starting over as that also has a lot of problems to work around. All tanks progress in slightly different ways, even if we can't do testing well enough to spot those differences.
So my move would be to look for what is wrong by testing the things we can test and making some smaller changes to get it working better. It may not be something that shows in tests but watching the fish may help more.
Some things like lighting, space and food are not so easy to spot if we don't watch our fish and get to know what to expect from them. Things like stress are often not shown on testing but if we watch we can spot it.
But I see no test results which leaves you kind of blind to any potential problems with those things we can test.

 

[deeda]

Was this a brand new or used tank when you got it?

Have you used any type of medications in this tank?

 

[Roboto]

Hi and thanks for the replies.

The tank and all things placed in it (except livestock and plants of course) are new.
I did do a around of paraguard over the summer which lasted 6 weeks and that I stopped in August. I've not used carbon since then, but I've done at least 15 water changes ranging from 30-50% since.

Parameters are similar to my other tanks in terms of TDS, KH, GH. (TDS 180-200, GH 6-7, KH 0-2) PH is 7.2 which is a bit higher than another tank (6.8) which has been very successful with bolivian rams and otos which have strugged in this problem tank, but since changing the substrate a few weeks ago it's been getting lower with each water change. The PH on this tank used to be alarmingly high considering how similarly I dealt with this tank compared to another community tank I have. This is what prompted me to change the substrate and remove a few rocks that had me questioning things. I did that change 4 weeks ago and have done 4 water changes since and the PH has worked down from 7.8-8 down to 7.2 where it is now. I thought I was out of the woods, and added 4 cories to give the 2 that remained from the 6 I got 8 months ago some company, but the 2 adults didn't really perk up and the four babies started to look lethargic so I moved them into my quarantine tank. I still have one adult cory in there because he's been quite challening to remove, but hopefully I'll get him soon enough.

Tank is 29 gallons.
Filter is an eheim canister 250 4+ (rated for 65 gallons) as well as a sponge filter seen in the photo below. Recently changed the filter pads and cleaned the media (not with tap of course). The media is about 8 months old. I have new media I can put in there and my sponge filter and pads are cycled so it shouldn't be an issue to make that change.

As the rasboras, pleco and amanos seem to be having no problems for months, I did a water change today and plan to leave them there. I'll see how the cories do in the quarantine tank which is a blackwater spa with indian almond leaves and if they start to perk up I may move a couple back for a week or two and see what happens.

Thanks again for any insight. I'm trying to do a few last things before tearing it all down and am a little sad to consider throwing away the driftwood, fresh substrate and maybe even the plants, but that's tank life...

 

[noraaustin72]

I think cleaning is a main issue for tanks.

 

[Discusluv]

Corydoras and German Rams ( which are essentially earth-eaters like geophagus sp. ) require a sand substrate. Try pool filter sand or other soft aquarium sand. This is key to a healthy group.