Backyard Aquaponics
A place to discuss aquaponics

I found these two fingerlings dead today. Does this look like disease or like other fish chewed on them?

Seen any herons hanging about? It looks like something grabbed the one with the wound on the mid section from above. Possibly the same sort of thing happened with the other. If it's a heron you'll probably wind up missing a lot of fish unless you put some netting or cover over the tank.

They are in a greenhouse so I don't think anything got in. Can fish that are similar in size cause this much damage to each other? Or could a parasite cause it?...... I am new at this.

It's tough to figure this out no matter how long you've been at it. It's generally not worth the cost of sending the fish to a lab or going to a vet. There's a chance you may never know what did this but since they are in a greenhouse and it looks more like a bite on that one with wounds around it's middle - Got any fish big enough to half swallow that one?

At least with some parasites you'll see fish do what's called flashing. Basically the fish rolls on it's side and tries to scrape the parasites off on the bottom (or some other object). Point being that you often see changes in behavior.

Sometimes you can figure things out by watching the fish for awhile, might spot a really aggressive one or see the fish behave strangely. Generally we suggest taking a look at the water parameters to see if somethings going on there, especially since fish deteriorate rapidly after death and that often hides the true cause of death.

Thank you so much for the info. I tested the water and it is good.
I found more with ulcers, Would you take any that have ulcers out and put them in a hospital tank?
I have read about several different treatments, do you have a go to recommendation?

Thanks so much for your time and advice!

Please post your readings from the tests very often people miss something

One thing I forgot to mention is it's possible they are getting caught in a pipe or other part of the system and this is causing injuries that result in death.

I think the ulcers are either wounds from being attacked, if not then they are likely bacterial infections, perhaps aeromonas. If bacterial, antibiotics would perhaps work but not in the AP system because they would likely destroy the bio-filter. If you want to go this route remove them from the system to treat them. I still think it's more likely they are injuries because of the ones I've seen, they don't look infected. Usually infection is accompanied by swelling, redness and other indications. I'm guessing these fish won't be eaten or at least not soon? Some Antibiotics can be toxic and many people are allergic to certain antibiotics.

In the meanwhile, try salting the AP system water to 1 ppt - use un-iodized salt. This helps the fish form a slime coat and lowers stress. I've included some other salting treatments in case you need them somewhere down the road. Some plants like strawberries are sensitive to salt.

Salting
Nitrite issues and general health - 1ppt = 1KG per 1000L or 1gm per L
Parasites - 3-6ppt
Dip for parasites - 30ppt - .5 to 10 minutes. Remove fish showing signs of distress immediately (laying on side or erratic behavior for example)

I think that's about all I can offer you, hope they snap out of it.