Backyard Aquaponics
A place to discuss aquaponics

Ok so gluttony seems to be the consensus.

It didn't pop but it did bubble a little. There was a little fluid in the abdonminal cavity which I didn't take much note of at the time. If you look at the photo you can see the fluid sitting on the plate and the remains in the cavity (note the very wet match end). When I slit the stomach open little bubbles bubbled to the surface for a couple of seconds. This may have just been because it had been dead for a little while.

I've got one other theory that I'll mention tonight so if anyone else see this please offer your comments.

With fluid in the cavity, then combined with the pale gills, you might start suspecting kidney disease and/or anaemia. If I remember correctly, the worst kidney diseases are highly contagious and you'd have mass deaths, but usually also come with loss of appetite (and that fish had certainly eaten!) and the fluid in the cavity would be yellowish-brownish, so I'd discount that horror possibility. If anaemia, the gills would be pale but so would the liver and gall-bladder and any blood might appear "thin" and quite viscous, so I'd discount this too... takes us back again to gluttony?

I'll have to wait for your other possible diagnosis...

The other thing I'm worried about is super high nitrates.

Because it has been so cold the plants haven't been doing much of anything. I'm about to order some liner to increase my water storage capacity. Once the liner is installed I'll do a water change and save the nutrient laden water for when my toms are super hungry in summer.

If the nitrates are causing a problem now though I'll have to dump it and lower the nitrate concentration to a more reasonable level.

Gluttony seems to be the appropriate diagnosis.

What are your nitrates sitting at?

Is it possible to save them up? How long will they last, and how quickly will the hungry tomatoes take them out?

Ummm more than 160ppm.

As long as they don't get used then they can be "stored" have to make sure the tank is covered so algae doesn't start growing.

I'll have to plant the tomatoes before they start getting used and I'm about to start seedlings inside soon.

"Excessive" nitrates are in the order of 300+ so I don't reckon you've got anything to worry about at 160. In an earlier trout season, my nitrates were regularly over 200 until the plants got going. Prolonged exposure to excessive nitrates will affect growth (abnormalities and/or death) but in the short term it's not readily apparent (with the exception of some "unusual" behaviour -- but with trout, they have lots of quirks, so how one puts it down to one or another is difficult!?)

Kudos for not wanting to waste water, but storing nutrient laden water will bring its own problems: easier to water the lawn with it instead. If you want the nitrates to fall then stop feeding for a week then reduce the feed from what they're getting now. If you do want to alleviate the nitrate situation quickly, do a 1/3 water change daily for a few days (your dirt garden will love you for it) whilst still holding off the feed. In a mature system, when you need your nitrates again, simply start/increase the feeding.

Just remembered to come back to this.

The feed I am using is a bit small 3mm but that is what happens when you buy by the bag. I've almost used the bag up so next time I'll be going to a larger pellet.

Is the skin darker then on your healthy ones?
Seems unusually dark to me. Are the lighter patches from handling or have you found it like that.
The gills are very pale too.
Just like with all other living things being overweight weakens the immune system and gives way to secondary issues.
And that one sure was a bit on the cuddly side.
Did you find tiny black spots on the cavity lining?

I think the pale patches are from handling.

Gills are pale but I think that is a symptom of it being dead

Yes did look a bit fat.

No black spots.

looks perfectly healthy to me apart from being dead.

Yeah that is pretty funny. Perfectly healthy apart from being dead