My 9 year old albino bushyose longfin pleco became bloated past 3 weeks and stopped pooping. Also became quite inactive and now sits in the middle of the tank instead hiding in his favourite spot. I tried blanched peas but he won't touch them. I have some epsom salt but I am not sure if it's safe to use on plecos and how to use it. My pleco has been with us for a long time and don't want to lose him. I'm not sure what to do at this point, any help would be greatly appreciated, thanks!
1. Water parameters
I checked the water parameters and they were fine, nothing out of the ordinary. I change the water once every week (30% water change). The temperature is about 28C(82F).
2. Tank set up
a) Size - 20G
b) Substrate - 3cm(1inch) of Resin pebbles
c) Filtration - Topfin hang-on power filter with Ammonium filter/Active Carbon filter/Sponge filter.
d) Furnishings - two pieces of driftwood, few rocks, one ornament
e) Other tank mates - none
f) How long has it been set-up - Almost 9 years
g) When was the last new fish added - 4 years ago
h) Foods used and frequency? - Before symptoms - twice a week he was fed a quarter of an algae wafer
3. Symptoms / Problem description
My pleco looks bloated in his belly area, his eyes are sticking out more than usual and he hasn't been able to poop. He no longer hides in his favourite spot and now usually sits in the middle of the tank. Beginning of the month the water had some whitish opaque slime that was encasing some of the food he didn't eat, after siphoning it out, the slime didn't return. Not sure if that's what caused his illness.
4. Action taken (if any) - Stopped feeding him wafers as it only made him more bloated. I tried feeding him blanched peas but he did eat any.
5. Medications used (if any) - Adding 10mls of Melafix daily for the past week with the active carbon filter removed. I wanted to try anti-bacterial/fungal medicines such as API Triple Sulpha or API General Cure but I found out all medicines have been banned in Canada recently and I will not be able to acquire any fish medicines other than ones like Melafix and Primafix.