[cthetoy]

My Goldflake has a gas bubble in its eye. I pop the air bubble but a few days later the skin heals where I popped the gas bubble and the bubble grows again.

I only had the freshwater Maracyn II and used it at the recommended dosage for 2 weeks but the gas bubble keeps reappearing.

I just order Maracyn II (Saltwater) and Furan2. Which one should I use now?

Water parameters are ideal. Fish eating well. In hospital tank currently.

[leebca]

The difference between the saltwater and freshwater formulas is not that much nor that important. You do wish to use what is intended for its application, though. So making an effort to do it right is a good thing.

Double the initial dose of Maracyn II from what is recommended on the package for another 5-day treatment.

Furan-2 is a very good antibiotic, however it is topical. This means its action is on surface bacteria. Maracyn II however goes inside the fish to deal with systemic infections, as well as works on topical infections. Usually an eye problem displaying with gas is an internal infection around or near the ocular nerve (behind the eye). To get at that, you need an antibiotic that goes inside the fish.

This treatment can be long with a great amount of effort. Use double the dose as noted above and if necessary, repeat the treatment for another 5 days (10 days at the double dose) even though you've used it before.

Good luck. Keep us informed.