New fish swimming at top of tank, sick???

[unknownsoldierr]

I got this fish at Petsmart about 3 days ago, and it's been swimming in the top corner the whole time. Other than the PH being at 8.0, nothing seems to be out of the ordinary. I put some stress zyme in yesterday so it probably isn't ammonia levels, nitrate or nitrite, as the stress zyme would've fixed the problem. I don't want to take the fish back to Petsmart as they'll probably let it suffocate in whatever bag I put it in. I'm also poor, but will buy medicine if the fish needs it. The only thing I've found that the fish could have is an internal fungal infection (someone on a random message board said this could be the case for someone else's fish that were swimming up top). It shouldn't be the oxygen levels either as I have a bubble stone, 3 real plants, and surface movement from my filter.

Tank specifics:
I have 4 other fish, 2 of them otocinclus (dwarf catfish, algae eaters), the other two I've had since I got the tank (since August). I just recently (a week ago) changed the gravel because of its algae growth, changed the water 100% over 3 days, and got some underwater plants from petsmart. 2 days after I inserted the plants is when I got the 2 otocinclus's and the sick fish. My tank is 15 gallons, and the filter is a standard E-Z filter from walmart with a carbon filter and one of those white sponges that collects muck. I had a fish with a bacterial infection before I changed the tank, some pink bacteria that grew in to nests of pink stuff, and a different new fish I got that died in 2 days. The new fish never swam around when I put it in though, so I don't think its swimming up top could be a symptom of a bacterial infection if it was that instantaneous. Who knows, though

If somebody can offer me any suggestion as to what to do, I'd love to take it. If I have to make a hospital tank for this guy, all I have is a 2 gallon bucket... but hey, that might work for such a teeny little fish. He's a very small tropical with a flashy blue tail.
Thanks everyone.

 

[i3k]

Did you actually test for ammonia/nitrite/nitrate? I wouldn't rely on stress-zyme fixing anything. Ammonia can cause damage to the gills and slowly suffocate the fish, which would cause it to swim at surface.

Since you changed out all the gravel...you might be going through a mini-cycle and have some ammonia present.

I suggest doing 50% water changes every other day and see if the fish gets better.

 

[tyspot1000]

Did you actually test for ammonia/nitrite/nitrate? I wouldn't rely on stress-zyme fixing anything. Ammonia can cause damage to the gills and slowly suffocate the fish, which would cause it to swim at surface.

Since you changed out all the gravel...you might be going through a mini-cycle and have some ammonia present.

I suggest doing 50% water changes every other day and see if the fish gets better.

+1

I also think you are going through a mini cycle. 10% of beneficial bacteria is on gravel, decor, etc while 90% of the rest is in the filter. Enough thats not much, It can still affect you tank.

If you happen to have the parameters of the tank, I would love to see and find out the problem.

If it is ammonia and nitrite in the tank, I would suggest doing 25-50% water changes everyday with addtional prime (Detoxifies ammonia and nitrite for 24 hours, giving you enough time till the next WC.) until the ammonia and nitrite go away.

Tyler