Sick fantail goldfish

[Canova]

Spot, our 8 yr. old fantail goldfish has been floating at the bottom of his tank for the last few hours. He swims for a few seconds and then stops, face down at the bottom of the tank. He is the only fish in the 30 gal. tank. After testing the water, the nitrates were high, so we changed 50% of the water. While changing the water we noticed tiny little worms swimming in the water. Does anyone have any ideas on what the worms might be? I've been reading about swim bladder but I'm not sure if that's what it is. Any advice would be appreciated.

Thanks

 

[jsoong]

I would not think that the worms cause the problem. Most mature tanks have some other critters in it (bugs, snails, worms, etc). Most are harmless (& good food for the fish). Parasitic worm tend to be attached to the fish rather than free floating.

How high is the nitrates? Very high nitrates may cause swim bladder dysfunction, and that will not be immediately corrected with just lowering the levels. <It takes time for the fish to recover, & long standing damage is permanent.>

However, this may not be buoyancy problem at all, but lethargy. With buoyancy problem, the fish has trouble maintaining it attitude <ie head may be pointed up or down>, or it has problem staying at the top or bottom of the tank. The fish generally is active and will fight against this. unless the problem is longstanding & the fish is exhausted from fighting (usu. a few days), it won't be just sitting at the bottom of the tank.

Lethargy is much more non-descript. This can be anything form cold temp, infection, starvation, parasites or old age. Is there anything else you noticed with the fish? Any spots, bumps, swelling, breathing rapidly, etc?