CorysRock

Hi all,
I have 2 albinos, 2 bronze, and 1 peppered cory at the moment and am thinking of getting another tank so i can get more.

I was in at the lfs today and the lady said that corys like soft water and she sold me some blackwater extract to put in the tank (which i did but only about a third of the reccommended dose.)

Was this the right thing to do, i have had 2 corys die over the last 2 weeks and she said it was probably because the water was too hard.

I also have 4 b/n catfish, 8 neon tetras and 1 albino red finned shark.

It is a 150lt tank.

Water parameters are:
temp 26
ammonia 0
GH 60
KH 0
pH 7.5
nitrite 0
nitrate 40

currently i am doing a 20% water change to try and bring down the nitrate.

the corys that have died just seemed to go very pale and hid all day, stopped eating and over about 2-4 days died.

i feed all my fish fish crumbles, algae wafers, peas, cucumber and occasionaly some frozen blood worms.

I would really like to know what it going on i dont want to lose any more fishies.

At the moment i use small smooth gravel as substrate.

ta

Barbrella

Your nitrates are at 40ppm, and that could certainly be what killed your corys. Corydoras are quite sensitive to high nitrates.

The BWE that the lady sold you will do nothing for this, and I suggest you don't ask petstore employees for advice any more.

How often and how much are you feeding?
How often and what volume of water do you change when you do water changes?

MissMTS

I have my cories in very hard water and they are doing fine. I doubt that is what killed them. You may want to try vacuuming your gravel to get rid of any wastes to bring your nitrates down. I'm sorry you lost them. They are such cute little guys.

susitna-flower

I love corys too! Welcome to Fishlore!

IF you really do want more corys you will have to move up to a bigger tank, or trade in a few of your fish. You are experiencing the problems of overcrowding.........

I agree 40 is too high for nitrate, especially for corys. It will take more than one water change to bring that down to an acceptable level. The vacuuming will help also, maybe 1/2 one day and 1/2 the next. I would do 2 - 25% changes in one day, then test the nitrate again. If it is still over 10 do the same again. Do this every day until you are maintaning your tank between 5-10 on nitrate. This is safe for most fish. I think if you are breeding some like discus you have to maintain it closer to 5......shrimp can also be super sensitive....

The main reason you are experiencing high nitrate is that your tank is overstocked. 150 l is under 40 gallons and the fish you described are in the tank already count around 48" of adult fish size. This croud would go better in a 55 gallon tank! Unless and until you move up, you will need to keep a close eye on your tests, and do water changes accordingly. Good Luck

COBettaCouple

Welcome to Fishlore.