Columbian Shark cats

[andywg]

A quick tip on brackish and marine tanks:

You NEVER add salt directly to the tank.

You dissolve into water in a container (most people do this overnight with an air stone or powerhead in the container) and then you water change taking out the old, weaker salinity and adding the new, stronger salinity.

If the fish were surviving at freshwater then the best thing is to raise the salinity gradually. No more than 0.001 SG per week. Otherwise you can harm the fish.

 

[Pufferpunk]

I would do a water change immediately, of about 80%. Do you have a test ket? Test the ammonia, nitrIte, nitrAte & pH. Do you have a hydrometer? How was the tank cycled? Dumping 5 cups of salt into a 10g tank will pretty much kill off everything--fish & benificitial bacteria. I think you have gotten way over your head with the whole BW thing. A 10g will support only 1 of these fish (they are schooling fish & don't like to be kept singly) & only for a short time, as eventually, they can grow as large as 18". Can you return the remaining live fish?