The water flow of the tank is pretty minimal. The ferts are elements and minerals not chemicals. I have only two full grown adults. I have 3 that are 3-4.5" Its really warm because I thought there was a fungus problem but what I thought was a problem went away and I just forgot to bring the temp down. I will start to lower it tonight. I've had otos in warm water for ever. Never had a death. Corys on the other hand are rather new but have shown no signs of stress.