My becko has a large swollen area behind her right pectoral fin

[Tanyaclick]

Hi Koi family,

I need some insight regarding my becko, who has developed a large swollen area behind her right pectoral fin. These fish have been living in a temporary pool for a year and a half while I work on my pond build, which has faced many challenges and setbacks, unfortunately leading to wasted money due to unprofessional help. This is my first pond build, and I never anticipated it would take this long. Fortunately, I have finally found someone competent who will finish the project in June. Until then, the fish will have to remain in the pool.

All water parameters are within acceptable ranges, including KH and GH, pH, nitrates, nitrites, and ammonia. I clean the pool and perform a 50% water change every two weeks, which is the best I can manage. About a month ago, I lost my first fish from this batch; I didn't notice it had started to float sideways and tail-up until it was too late. This happened just a couple of days after the initial signs appeared.

The becko that is currently injured jumped out of the pool accidentally a few weeks ago. I treated the pool with ProForm C for three days, along with multiple rounds of Melafix after her jump a few weeks ago.

Yesterday, I netted her to take a closer look. There wasn't much to see besides the swollen area. I've been administering Melafix for a couple of days, and I added a small amount of salt water at 0.04% yesterday. I added more melafix today. She looks a little better.

Any advice or opinions you could share would be greatly appreciated. Thank you!

Here is a video https://youtube.com/shorts/Ifng-TqlP...c391lM1gOfmW-J

[fly4koi]

Lesion, if you can do Baytril injection that's the best, otherwise tricide neo or oxolinic acid.

[Tanyaclick]

How can I get baytril? Is the alternative topical?

[richtoybox]

Yes, the Tricide Neo can be done as a topical. It is a dry powder, which can be applied with a cotton bud/swab. The package directions are to use it as a dip, with the one gallon packet mixed with one gallon of distilled water, but the cheaper and easier way is to rub the side of the fish to get some of the slime coat on the cotton bud, then dip this into the packet to get some of the dry powder included with the slime coat and then rub this on the sore area. Take the balance of the packet, place in a sealed bag and freeze until the next time it is needed. Melafix is really not a very good treatment for any sores, and Proform C is for parasites, not infections.

[Tanyaclick]

The ProForm C was because they were flashing when she jumped out of the pond several weeks ago so I treated it for seasonal parasites.

[Tanyaclick]

Do you know what could have caused this lesion?

[fly4koi]

Sometimes bad water causing stress on the fish, sometimes it's a secondary infection because parasite compromised the skin of the fish. Have you order the med yet?