Help! I Hope I Put This On The Right Board...

[paigeyduckie]

My little cousin has a 10-gallon fish tank and their lives have been in a bit of disarray. I went over to their house (they live like 2 miles away) and cleaned their fish tank that was bombarded with algae.
They admitted they had not cleaned the tank in over three months.
So I gave the entire tank a scrubbing with clean water, rinsed the gravel substrate and scrubbed down the decor. I also scrubbed down the filter and changed the cartridge (it had a good 1/4 in of thick algae on it). Finally, I replaced the four fish (I acclimated them to the new water). Unfortunately one died when they were waiting for their clean tank.
Once again, it has been hectic and I completely understand how this could have been ignored (we all have our situations) but I did give my cousin a talk about responsibility. They got their fish from Walmart and I researched what they were:
One was a Bala Shark (there were two but one died)
I believe another is a Columbian Shark but I do not know for sure it has ALOT of whiskers.
I have no idea what the third one is... I'll try to get a picture soon.
All these fish were small when they got them but of course, over the course of a year, they have grown quite a lot. I convinced him that I would do something about the fish so they could have a bigger home and I could get him some fish that were appropriate for his tank size.

So now I'm stuck on what to do. I talked about it with my mom and were thinking that they might be diseased and no one would want them. So here are some options that I want opinions on:
1: Try and find someone who can take them diseased or not
2: Wait for them to die
3: Humanely kill them? I don't think I could do that... same with number 2
Any other ideas?
Please tell me your advice...

 

[Fanatic]

Answering your questions:

1) I would really search, and ask to see if anyone is willing to do that. Try rehoming to your LFS.
2) No, don't wait for them to die. Try to heal them instead, if that's the way you want to go.
3) Wouldn't do that either, if they aren't suffering, don't euthanize them.

 

[Ilovemyloach]

What disease do you think they have?

 

[TexasDomer]

By changing out their filter cartridge, you threw away any bacteria colonies they had. Now the tank has to re-cycle, so you really need to be good about doing water changes to protect the fish from ammonia and nitrite poisoning (since the family doesn't seem to want to do that).

Going from a really dirty tank to a really clean one can shock and kill the fish. I know it's tempting, but next time it's that bad, do lots of small water changes rather than one really big one.

The bala and Columbian shark will be really hard to find proper homes for, as they get over 1 and 2 ft. They are likely already severely stunted. Due to both of these issues, I personally would euthanize them. They will not be living a good life in this tank, and you will have a hard time finding someone with a big enough tank to keep them healthy.

 

[Sel]

Ooooof, ouch, yeah, letting a tank go for that long and then cleaning it like that will cause the tank to crash. It's how I killed my first tank as a teenager. They all ended up dying over the course of 24 hours. I had no survivors.

 

[Nataku]

What gives you the idea they are diseased?
Instead of euthanizing you could try curing whatever ails them and then it may be easier to rehome them.
But to do that, we would need to have an idea of what is wrong with them.
How are they acting? Any visible white or other colored spots? Open wounds?
A 10 gallon is a good sized quarantibe tank in any event.

 

[Kysarkel000]

We can help identify them and see if they might have a sickness if you sent us a pic and/or a video of them

 

[paigeyduckie]

Hey guys! Thanks for all the quick replies! I just got back from fall break and am back at my dorm now so I'm not with the fish. I'll get my aunt to take a picture of the tank for all of you so you guys can identify and see if there is any sickness. I'll ask if they have been acting weird too.