Sounds like you may have just joined the bichir bloat club. Polys re prone to this if there's no salinity in their water and they don't get much plant matter in their diet. Here's a plan that works wonders, against bloat, in polys and lungfish (other african species as well):
1. Remove carbon/resins from filter.
2. Perform a 30-50% water change (reduces free-floating bacteria population)
3. Add salt (teaspoon to a tablespoon per gallon) to aid the fish's osmotic regulation processes.
4. Treat with 250mg/20gallons of Metronidazole (Flagyl)
5. Leave for 3 days and do not feed.
6. After 3 days, perform another large water change.
7. Replace the salt.
8. Add full dosage of Metronidazole.
9. Wait another 3 days. During this phase, the bloat should be decreasing in appearance. In large fish, the water may take on an ammonia odor from the high volume of urea the fish should now be producing due to reducing the bloat and recovering renal activity.
10. 3rd day, another water change. Also, replace the salt and redose the metronidazole (full dose). If the fish looks to be well on the road to recovery you can offer a small feeding each day.
11. Another water change. No meds but, I'd recommend the salt. You should be clear now.
This is the treatment I use on my africans, puffers, and my lungfishes/polypteridae. Knock on wood that it's worked every single time.
i have a 2inch senegal. recently he looks like he ate something almost as big as he is. his middle section is huge. i,m not missing any little fish and only feed it 2 shrimp pellets a day. it is so fat that only its belly touches the sand. any ideas on why the sudden wieght gain
