Backyard Aquaponics
A place to discuss aquaponics

Just in case you might want to look at the ammonia levels in your fish tank. They don't always float when they die. I think probably they are just stressed as you mentioned. When they get skittish they don't like to come to the surface but they may be eating the food off the bottom of the tank.

Had another dead catfish today... one of the smallest ones. Noticed what looked like ich, but the white dots were few and far between, not like the pictures I've seen where it looks like someone tossed a handful of salt on the catfish.

This one had no obvious signs of duress, no missing barbels, no fin damage, no sores or bleeding. It's mouth and gills were wide open.

I'm kind of at a loss here, feeling frustrated because I still have no idea what the heck is going on or how to fix it.

Additionally, my channel cats are STILL not eating the organic pellets i bought (which contain no fish meal i believe). They hide 24/7 at the back of the tank.

I'd up your salt to 3ppt (more if you don't have things like peas and strawberries growing). Add it in one quick go.

But I think wide open gills and mouth can be a sign of poisoning (or rigor mortis). The tap wasn't left on when topping up? Chlorine can do it.

I added 55 gallons of water to the system today, several hours prior to finding the dead catfish. The 55 gallons was tap water that had been sitting in a food-grade coated/sealed steel barrel for 2-3 days. I've used this barrel numerous times before with no issues. Prior to me getting the barrel, it held strawberry syrup.

All the catfish have been flashing for a while but information I've found online suggests that channel catfish do this when the salt irritates their skin... right now the salt levels are at around 0.7-0.8 parts per thousand.

How much salt should I add to 600 gallons of system to bring it up around 3ppt?

And, after salting and letting the system run for a week or two I'd need to do a water change to get rid of some of the salt? I have read that plants use tiny amounts of sodium and/or chlorine but I don't know how long it would take for the levels to drop.

From reading up, catfish should be fine up to 3ppt, they don't like it, but should be fine. I've never had them before, so I can't tell you from first hand experience.

But 600 Gallons is approx 2200L. 1kg in 1000L of water makes 1ppt, so 3kg salt to make 3ppt. You want about 6.6kg of pure salt total (14.5 pounds). I hope you see how much easier metric is in these types of things.

One of these will let you test it:
http://www.ebay.com.au/itm/Portable-Sal ... 25a924c132

Thanks. I'm aware of the superiority of metric but unfortunately in the US it's really hard to switch because you find yourself having to translate whenever you talk to a third party, like a clerk at a store for example.

I had to buy a 50 pound bag of the pool salt I'm using (100% pure solar evaporated sea salt, no iodine or caking agents), so I have plenty of that. I'm not sure if this disease is ich or something else, but I was reading that ich can be treated by raising the water temp to 85F for 7-10 days which will hinder it from reproducing. Should I try that first?

Raising the temp will increase their life cycle, so they'll breed quicker, attach quicker. If you've got enough salt, it'll mean that you'll break the cycle of the eggs, etc. But without the salt, you'll make it worse.

Well, three more dead this morning. Ammonia and nitrites showing close to zero. Also none of the other fish species are showing any signs of distress or disease. Only catfish are having problems. All 3 deceased looked like this:





I added some salt but without a salinity refractometer, I don't want to overdose it. Also, i don't have a scale (yet) so i'm measuring out salt by volume instead of weight and converting it as best i can.

Hi cathode
Nothing sucks like losing fish.
One small comfort I take is that in fish destined for the table you have two choices. Salt or dispose. You have salted to minimum1ppt so IMHO you have done all you can.
Fuzzy white spots as you initially described the condition affecting the fish are probably a bacterial condition called, ‘columnaris’ or a, fungal (ish) condition called saprogenia . In salting you have done the right thing to combat both of these.
The bacterial infection commonly affects the mouth and this would be my best guess from your photo. It is a guess I have no experience in cat fish.
The fungal infection has the appearance of fine strands of cotton wool.
If you have access to a microscope I understand that the bacterial infection will have a.”rod” like configuration.
OK; This is me in grandfather mode. Set up a quarantine tank and use it whenever you introduce new stock.

I grew up with songs about catfish on the Bayou. One day.

The dead catfish have become food for the black soldier fly bin. I just got my starter kit of larvae about a week ago and they so far have devoured an entire 3-4lb watermelon that had started to go bad. They'll probably take 6-8 hours to eat up the three dead catfish.

I've salted to approximately 2.5 ppt, if I see no change in behavior and/or dead fish tomorrow i will bump up to 5-6ppt and then do a water change in a few days. I don't have much important stuff growing in my beds yet so i'm not real concerned there. The other fish sharing the same water are guppies and 1 tilapia which I understand the guppies can tolerate brackish water easily.