Fish Disease

[de54engine]

Hi, my name is Lisa. I am new to the forum but have been keeping fish for over 10 years. Always had success until about year ago. Fish started mysteriously dying and my shrimp population went from dozens to one. I thought it was age or perhaps in the case of the shrimp some hungry indian pea puffers. Went on vacation in late May/early June (cleaned tank well before i left and had someone feeding them). Came home to several dead fish which i hoped was just overfeeding. Then i lost my puffer who was always the spunky one (he never bothered other fish, was very social and fun). This was followed by the first real visual evidence (see pic). At this point, i had hand surgery and serious cleaning was delayed by two months. Levels read fine on dip test but sure something was off. The rainbow fish continues with the pictured sore (this is pic from today). Rest seem fine. 55 gallon tank. Established in 2019. Did have to get new filter recently (treated with stability as rec by fish store). Tested levels with API test kit and ammonia was off chart. Did several 25% water changes (with gravel cleaning/added Prime), added Ammo Lock with nitrifying bacteria as rec by API booklet that came with test. (then realized the test expired two years ago) over past few months tried erythromycin, melafix/pimafix and kanaplex (at totally separate times with carbon placed back in to remove medicine) to treat entire tank assuming fish would continue to die. No new fish deaths but no improvement in rainbowfish. Everyone seems fine- eating, swimming, socializing…current occupants: one dwarf bristlenose pleco, about 7-8 dwarf cory cats (all born in tank), two yo-yo loaches, two purple tetra, one blue eyed rainbowfish, two black neon fish, two rummy nose rasbora, one amano shrimp, one tetra (orange stripe), two green tiger barb, one ruby tetra and one glo fish i got stuck with…dip test shows PH approx 6.8-7.0, 0 Alkalinity, 0 nitrite, nitrate, free chlorine and iron. Going to get new master test kit today. Tried several salt baths for the sick rainbowfish but he just looks the same. Trying to save him and rest of tank of anything else is in there. HELP!!

 

[Tomsfish]

Look into Lymphocystis.
It is viral and has no treatment.
Often a fish can recover on its own over time with good fish care [clean water and diet].
My understanding is it is not contagious.
Welcome to TFF.

 

[de54engine]

That was kinda what i was leaning towards…initially it looked more whitish so columnaris kept coming up and which accounts for some of the treatment. Knew there was a drop in water quality when i was laid up with hand too. Everything appears to be where it needs to be now altho grabbed new testing supplies today to be sure. Can you recommend a top of the line food that may help boost his resiliency? Thanks for your insight.