I need help identifying/treating a possible disease in my tropical community tank.
I came into the Aquarium Co-op about a month ago for advice after a couple of fish mysteriously died a few weeks apart and another one was showing white spots. Unsure if these issues were related, I decided to treat the entire tank. A nice young man working at the co-op looked at a photo of the fish with white spots, said it doesn't look like ich, and advised I try adding aquarium salt and Maracyn first, followed by Ich-X and Paracleanse if that wasn't effective.
After finishing the treatments with salt, Maracyn, and Ich-X (and removing almost all of the salt through a series of water changes), one of my cory catfish died unexpectedly this past weekend, after which I began treating with Paracleanse. Then today I noticed a black neon tetra apparently on the brink of death, losing most of its color and struggling to swim. That fish is currently in quarantine and I don't expect it to live much longer.
My question is: Should I try treating the tank with something else, since the salt/Maracyn/Ich-X/Paracleanse treatments haven't cleared up the white spots on the black neon tetra and two other fish have died since starting the treatments? And should I give my fish a break before trying something else?
No other fish have visible symptoms at this time. I suppose it's also possible that these fish could be dying of old age, as I've had them all for more than 2 years, but it seems odd that several fish have randomly died within two months of each other when there had been no other deaths in this tank since it was set up back in early 2021. The white spots on the black neon tetra definitely seem suspicious, although they appear to have gotten just slightly smaller over time.
The tank is 29 gallons, has several live plants, and currently has the following stock:
– 6 Florida Flag Fish
– 5 Lemon Tetra
– 4 X-Ray Tetra
– 4 Black Neon Tetra
– 5 Albino Cory Catfish
– 1 Bristlenose Pleco
– 8 Nerite Snails
Ammonia: 0
Nitrite: 0
Nitrate: <5 ppm
PH: 6.8-7.0
Temperature: 77 F
Filtration: AquaClear 50 HOB filter with carbon filter and Purigen, plus a 20-gallon sponge filter
In case it's helpful, here's a log of recent events, with deaths and symptoms in bold:
(Note: This list doesn't include all water changes. I diligently do a 30% water change every weekend in addition to what's listed here.)
Feb 4 - RIP Paradise Fish
Feb (?) - Euthanized an X-ray tetra with an apparent spinal deformity that was struggling to swim and eat. This was a long-term problem that got only recently got worse. Not sure if this fish had a disease or if it simply had a "birth defect," but I suspect the latter.
Feb (?) - Quarantined a bloated Black Neon Tetra, treated with Tetra Lifeguard + aquarium salt for about a week and returned to tank in apparent good health
Feb 20 - Added 6 Florida Flagfish
March 13 - RIP Silvertip Tetra
March 14 - Noticed white spots on a different Black Neon Tetra (irregularly sized, raised lumps that do not look like ich)
March 15 - Added Maracyn and aquarium salt (2 Tbsp), removed chemical filtration
March 16 - Maracyn dose #2 + more aquarium salt (4 Tbsp, so now 6 Tbsp total in tank)
March 17 - Maracyn dose #3
March 18 - Maracyn dose #4
March 19 - Maracyn dose #5
March 20 - 30% water change and replaced chemical filtration (carbon filter + Purigen)
March 22 - Began Ich-X treatment (after another 30% water change and removing chemical filtration)
March 23 - Ich-X dose #2 (after 30% water change)
March 24 - Ich-X dose #3 (after 30% water change)
March 25 - Ich-X dose #4 (after 30% water change)
March 26 - 30% water change, replaced chemical filtration
April 9 - RIP Cory Catfish
April 9 - Added Paracleanse (first dose) after 30% water change and removing chemical filtration
April 11 - Paracleanse dose #2
April 12 - RIP Black Neon Tetra, probably (not the same one with the white spots, that fish is alive and seems to be doing well but still has the same white spots. Unsure if it's the same fish we previously treated for bloat)
April 13 - Planning to do another 30% water change and replace chemical filtration as the Paracleanse treatment is complete