Backyard Aquaponics
A place to discuss aquaponics

Hi All! I have had my system going for over a year now and its been going good. I started off with Catfish and quite a few of them died during cycling the system, but in the end I was left with 7. Then I added some bluegill after the system fully cycled. I have an IBC tote for the fish tank, and three grow beds with clay pebbles. Attached is a picture of my water test results and other than Nitrate the others are staying very steady for the last several months. I have my setup outside and since it is winter here my water temperature has dropped to about 50-55 deg F.

So on to the issue... About 1 month ago I noticed some spots on one of the fish and found some info online that said it should go away on its own so I decided to wait it out. But that spot has stayed there and then today I noticed the second smaller one that must have been hiding in the back for the last little while. Is this something that I should be worried about and if so what should I do?

I don't think the water parameters are a problem. It looks like either a predator tried to nab the fish or you've got some sort of an infection going on. If your tank isn't covered then I'd do that - net it off or whatever you can. You can salt the system to 1 parts per thousand (ppt) to help the fish with stress and building a slime coat (this will kill any strawberry plants in your AP system). You can remove the affected fish to a quarantine system to heal and salt it to between 3 to 6 ppt. Last of all you could prepare a higher concentration salt dip for the fish if you don't have a quarantine system. I don't remember right now what that last one will be in ppt, I'm thinking probably around 15ppt but don't take my word for it.

You might also look and see where the fish is hanging out - is it hiding where it might rub up against something to cause this?

Thanks for the reply! I dont have any strawberry plants so I can salt and not worry about that. Any specific type of salt?

There is only one pipe that I will remove, the other pipe is the SLO but no sharp edges on that. The tank is covered so I think I am safe from predators.

NaCl (aka Sodium Chloride and table salt). Depending on how much you need the bulk bins at your grocer or pool salt are a couple ways to find it.

The SLO might still be a problem if they hide under it and can rub against the holes. I switched to a center drain (in a round tank) because I could see the fish better but there are lots of SLOs that run along the bottom without troubles.