Corydora swimming erratically

[bianca_m35]

So I had 3 peppered corydoras originally who have been in the tank for probably a year. They have been active swimming and searching for food. Just about 2 months ago I added 3 bronze corydoras. 2 males and 1 female. For the first few days they swam up and down like crazy and the female would literally slam herself into the substrate and swim super fast zigzagged and then stop to rest for a few minutes. Eventually this behavior stopped and they started schooling with my peppered corys, all was well and they stopped the swimming behaviors. Just recently I was quarantining a male veiltail betta with ick. All of ick went away and the day I was going to transfer him into a 10 gallon planted aquarium he escaped into my tank somehow and my other betta beat the crap out of him. Luckily hes doing fine and his fins are already growing back now so thats good. But it doesn't seem like the veiltail betta touched the corys or any of the fish at all. All of my fish are acting completely normal except the corys. Even my peppered corys seem scared. The bronze cory female is swimming erratically again but this time just swimming extremely fast and resting for a but then doing it again not throwing herself into the ground. The other 2 bronze are hiding then freezing then swimming fast then searching for food then swimming erratically again. My peppered corys seem relaxed in their swimming but are also hiding and not coming out when I go to feed them. I genuinely have no clue whats going on. I did add salt to my tank if that makes any difference. There are no parasites on any of the fish either. Idk if the betta may have scared them but they were so active and searching before on the bottom and now just stuffed in the corner scared. I tested my water and the quality is perfect. I followed 1 tbsp per 5 gallon for aquarium salt. Please help

 

[mrsjoannh13]

How big is the tank that the corys are in? When you say the water quality is perfect what do you mean by that? Can you post your specific parameters - ammonia, nitrite, nitrate, GH, KH, pH, temperature. What substrate do you have in the tank?

Is it possible the betta that is in the tank (that beat up the other betta) could be aggressive towards the corys? Some bettas can't be kept in a tank with anything else so have you seen any aggression?

I'll let others weigh in but I think corys might be sensitive to salt. I believe I read that somewhere but not speaking from personal experience.

Last comment or thought is that corys should be kept in groups of 5 or 6 of their own kind. So 6 peppered, 6 bronze, 6 panda, etc. Otherwise they have some issues feeling safe and secure that could be affecting their behavior. Just a thought.

 

[bianca_m35]

How big is the tank that the corys are in? When you say the water quality is perfect what do you mean by that? Can you post your specific parameters - ammonia, nitrite, nitrate, GH, KH, pH, temperature. What substrate do you have in the tank?

Is it possible the betta that is in the tank (that beat up the other betta) could be aggressive towards the corys? Some bettas can't be kept in a tank with anything else so have you seen any aggression?

I'll let others weigh in but I think corys might be sensitive to salt. I believe I read that somewhere but not speaking from personal experience.

Last comment or thought is that corys should be kept in groups of 5 or 6 of their own kind. So 6 peppered, 6 bronze, 6 panda, etc. Otherwise they have some issues feeling safe and secure that could be affecting their behavior. Just a thought.

Ammonia 0, nitrates 10, nitrites 0, ph 7.6, dh 6 temp 83. Sand mixed with pebbles, their barbs are fine though ive been monitoring. The tank is 45 gallons a long tank not tall. The betta is not aggressive towards any fish in the tank and neither was the one that escaped. My original betta only attacked the other one. I will be getting 3 more for each cory group soon!