Hi, I have a black moor goldfish. A few months ago in the summer when it was 40 degrees my fish started floating on the surface and going on his belly.
The first thing I did was look online and saw that this is a problem with their swim bladder, so I tried fasting my fish for 5 days then giving peas, nothing worked.
So I went to the local aquarium shop and they gave me blood worms, they seemed to do the trick and he was fine again.
But during the past 2 months my fish seems unwell and nothing is working not even the blood worms, he floats on the top of the water 24/7 (keeping balance unlike before) occasionally going down to the bottom or sitting on the gravel and when I move him he falls like a stone.
Any answers would be appreciated I'm really stuck here.
Also am I feeding him correctly, he has 4 sinking pellets a day.
This is a common problem and, given what you've tried so far, I think there's a very high chance that this is caused by impaired water quality. Rather than wait any longer, I'd set about doing a daily water change of anything between 25-50%. This might actually resolve the matter altogether.
I'd definitely get a liquid-based test kit, if possible - e.g. API Master testkit - as they're much more accurate. The 5/6-in-1 test strips don't have the crucial ammonia test on them, while some of the readings on them can be wildly inaccurate, especially PH/GH/KH.
I meant to mention the 4 pellets. This doesn't sound like very much. What brand of pellets are they so that we know what size you're referring to? Many years ago, when a beautiful veiltail goldfish I had suffered from swimbladder problems, I reduced the amount of food I gave her in an effort to counteract the problems. Similarly, when my common/comet goldfish started having buoyancy problems years later, I reduced his food intake. It was only afterwards that I realised I had probably overdone this on each occasion and that weakness/starvation was ultimately involved to a certain extent in their fatal demises. I would see whether more frequent water changes addresses the issue and, if so, then slowly increase what the fish is eating and ensure that chopped pea and live/frozen food is included in the diet.