One possibilty is that the fish is overeating/and or has some kind of blockage. Even if you are not over-feeding some fish have a talent for getting more than their share and when this happens they tend to look a little bloated and sit around around between meals.
So try this:
Partial water change of 30% and siphon the gravel. Use a good quality dechlorinator.
Add Epsom salt at the rate of 1 tablespoon per five gallons. Dissolve it first and add it gradually over 6-8 hours time(Epsom salt works as a laxative but it will also raise the GH of the tank--NOT a problem as long as it is done gradually)
Fast the entire tank for 24-48 hours.
You're right to be concerned as its not normal for these fish to sit. Even if it's 'just' overeating it can quickly turn into a serious situation for the fish if it's not dealt with.
Let me know how it goes
Robin
So try this:
Partial water change of 30% and siphon the gravel. Use a good quality dechlorinator.
Add Epsom salt at the rate of 1 tablespoon per five gallons. Dissolve it first and add it gradually over 6-8 hours time(Epsom salt works as a laxative but it will also raise the GH of the tank--NOT a problem as long as it is done gradually)
Fast the entire tank for 24-48 hours.
You're right to be concerned as its not normal for these fish to sit. Even if it's 'just' overeating it can quickly turn into a serious situation for the fish if it's not dealt with.
Let me know how it goes
Robin