GSP all black and sad!

[TonyGSP]

Hi!

Our GSP is around three years old, at least, that’s about as long as we’ve had him.

He’s around 3.5 inches long, in a 125 litre tank with external Eheim filter, on his own.

Up until the last couple of weeks he’s always been quite active and sociable, will come up to the glass to see you and ask for food regularly. The last 10 days or so he’s spent most of his time in one corner, black belly/dark back, not asking for food (though he did eat a small piece of fish we put in but is totally disinterested in everything else) and not pooping. When he swims around (rarely) his colour is bright, white belly and luminous spot on his head, but for around 90% of the time he’s just a black mass in the corner.

Does anyone have any ideas? We’ve read about dormant times when they have growth spells but this seems so out of character.

Nitrates 0
Nitrites 0
Ammonia 0
Phosphates 1.0 (was up at 4.0)
Salinity 1.011
pH 7.8

[Pufferpunk]

What is your water change schedule? What test kits are you using? An established tank should be showing some nitrite. What foods does he like? Fish aren't the best diet.

[TonyGSP]

Thanks for your reply.
We water change approx 30% weekly, always have done. Debris/excrement siphoned our as it appears.

We use the API test kit (the bottles of solution), with the salt water colour cards as advised by our fish store.

He loves (usually) cockles and muscles (in shells), scallops and sardines are another favourite. He never really liked snails so we don’t give them to him anymore. He doesn’t have live food (our own reasons, we didn’t know what he needed when we got him and wouldn’t have brought him home had we known!).

Not sure why the nitrites are at zero, perhaps we’re reading the card incorrectly?

There’s also lava rock in the tank which he regularly attacks. At least he did when he was himself!

No change still today, he’s had a swim for about 30 seconds and back in his corner all black. Still no poops either..

[Pufferpunk]

Are you shaking the nitrate test bottles ad directed? Go ahead & try adding Epsom salt at 1-2 tbsp/10g, in case he's constipated.

[TonyGSP]

Thank you.

Do we add the Epsom salts all at the same time, with him I the tank, or add to to water first then to the tank?

Thank you so much for your help

[Pufferpunk]

You could dilute in water 1st but it doesn't really matter. It's just magnesium.