Panda coris didn't like the new house

[Big C]

I moved my three coris from the 30 g to the new, cycled 75 g almost a month ago. They never seemed to adapt 100%. In the smaller tank they were always together in the new tank they each found a spot to hide. They were coming out to eat but always on their own. They didn't play much either.

When I came back from a week long trip last Friday, i noticed that one of them was nowhere to be found. He was the runt of the litter and never seamed to grow much like the other two. I looked for him everywhere, changed the water moved the rocks, etc. but i guess he died earlier in the week, nobody at home noticed it and he must have been eaten by the other fish.

This morning I found another cory dead! I'm so sad.

The water is good, all the other fish seem well. I don't know what's going on with the coris. The third one is not a very happy camper either, he eats, but it's not very active. Any ideas?

 

[Meredith]

What are your params? It could be that if you are totally cycled (no ammo, no trites) its just a lack of buddies. Those three corys in the 75 gallon had lots of room to spread out and it could be they felt lonely. Corys like to be in groups, the bigger the better. I would go and get more corys (qt if you can) and see if that helps out at all.

 

[Acer]

i have had this problem recently.. im pretty sure i remember that cory come up to the surface to breathe? it could be that they might be having problems getting to the surface due to the tank being too tall? i never had a problem with corys in my 29 gal & 10 gal and just last week i had 2 cory die. i have schools of at least 4 different types of cory so i dont think the lack of schooling buddys was the cause of them dying..

 

[QTOFFER]

Panda corys are one of the least hardy cory species, so I've been told.

I agree that corys are happiest in big groups, but I wouldn't expect them to die from loneliness within a week. Something tells me that either the corys were sick when you got them, or there's something going on in the new tank.

What are your water parameters, and how often do you do water changes/gravel vacs? Because they live so close to the substrate, corys are especially sensitive to dirty substrate. They also need rounded, smooth substrate. Look at the mouth barbels - it they're eroded away, then the substrate is either too sharp, or needs a good cleaning.

 

[Big C]

I think Qtoffer hit the nail on the head. The substrate I have in the big tank is fluorite (on top of eco-complete) which is much smaller and sharper than the rounded pebbles in the 30 g.

I do 40% pwc weekly parameter are:

NO2=0
NH3=0
NO3=10 (this may be a little low but the new fish will contribute to increase this parameter!)

It is hard to do gravel vacuums because the gravel is so fine. But there is no much debris on it -at least it' is no visible.

I'm planning to have tiger barbs in the 30 g. I don't think they are good company for the corys, are they? Should I bring lonely cory back to the lfs or just let him be and see how he fares?

Is the substrate going to affect my loaches the same way? I have 2 clown and 3 yo yo that look pretty happy so far. :?