mystery fish muncher...

[vampirefish]

hi everyone! in one of my tanks i have:
1 siamese fighting fish (male)
6 black neon tetras
2 neon tetras
1 pygmy cory
2 cory sterbai (i think thats their name anyway)
about 6 male guppies
1 zebra loach
but anyway, they've all been getting along fine for about a year now, but suddenly some mystery fishy has started snacking on the others! they keep getting more ragged and one of the corys has had one of his fins bitten off! i'm really confused because they've all been happy as pigs in mud until now and i have no idea which fish has caused the problem!

 

[DesignsOnYou]

How big is your tank? Is it cycled? Also, you could google "fin rot" and look at some pictures. Does it look like that? If not, I'm not sure who the culprit could be. Bettas can attack other fish that they perceive as male bettas, but a cory shouldn't be a likely candidate, I wouldn't think. Other people should have more input.

 

[BlueStraggler]

What are being eaten the tetras? or the guppies?

tetras are fast and should escape a cory...betta...guppy and loach.

OR, maybe none of them are being eaten but a bigger issue is at play.

 

[homebunnyj]

Sounds more like fin rot to me. It's usually caused by poor water conditions. Can you test for ammonia, nitrite, and nitrate and post up the results, in numbers, please?

What size is your tank? How do you maintain it -- water change schedule, feeding, filter maintenance, etc.?

 

[vampirefish]

it's mostly the corys that are getting eaten, and the only fish acting strangely is the pygmy cory, but i think something's stressed him. i'm not sure about the size of the tank because it's a tall round one (stupid idea but it was a present) but it's cleaned at least once a week. one of the tetras seems to have a bit of fin rot but it didn't go away with treatment and it's not spreading so i'm a bit confused :S

 

[misterking]

I had a zebra loach that got pretty aggressive once, started fin-nipping so I took him back to my LFS. If it's not that it sounds like a bit of a mystery, if it were your betta he'd go for the guppies' long tails.. Neons are general extremely placid, as are black neons, and even fin nipping tetras are unlikely to be interested in lower-region fish.