Please help if you can - I've had what is either a shubunkin or koi for 7 years - 20 gallon tank (he's the only fish) with a marineland filter rated for a 30-50 gallon tank - with a charcoal filter and a packet of gravel that's supposed to help with ammonia control. There is aeration and a heater in the tank set at 68 degrees. Ammonia, Nitrate and Ph levels are said to be appropriate as per local aquarium store.

He has had this issue all this life but never this bad. Stringy poop 6 days ago which I didn't realize at the time was a sign of the constipation starting again. Always used to give him dried food morning and night and 2 peas (shelled) at night (the peas always seemed to keep him regular)- so decided to just give him peas - reluctant to eat, generally just stayed in the tank with his head down and his body almost straight up in the air - continued trying the peas for 3 more days. 2 days ago got very worried as still no poop and area where poop comes out looks extremely large and whole area looks swollen. No other signs of disease - he will swim at times but generally stays in that same position - almost vertical. So, 2 days ago gave him 2 drops of cod-liver oil and then no food. The next morning coudl see poop visable in area but looking around the tank later in the day found no poop and hole still VERY swollen and large looking. So 2 days later here we are - have not fed him - don't really know what to do at this point. Did do a 25% water change 2 days ago also.

Sorry if this sounds all over the place - I really love the fish and any ideas or thoughts would be great - do I do more cod liver oil? Epsom salts? Something else? Please help! Thanks!

update - fish getting increasingly agitated - appears to be getting larger - decided to try epsom - 1 Tb. + 1tsp. in 7 1/2 gallons conditioned water - leaving him in for 10 minutes and then back into regular tank....hopefully will poop tomorrow....

You need to answer the other Qs in the box above.. concerning your water changing regime.

Could you let us have these including those readings for ammonia/nitrite/pH and nitrates as all these can cause this symptom. Constipation is actually way down on the list of likelys. Please do not trust what your LFS says, we need the actual figures.

That bag of gravel you have for ammonia reduction? Is that zeolite by any chance? Only its effectiveness expires after a week or two and needs replacing with a new one - zeolite or ammo chips bind ammonia for a period of time only.. and then unbind the ammonia and release it ALL back into the water.

Ammonia at any level causes flipover as can high nitrates or sudden pH crash. Water issues have to be eliminated first which is why the white box of Qs helps us help you so much

Please....don't give a lot of credence to what the lfs tells you about your water params.
Their possibly well meaning but bad advice have caused more problems than help to most of us here on the forum.

Hi Melfish, how is your sick fish now? Did the epsom salt treatment work?