Betta has odd discolored patch and ragged, torn/missing fin


Thank you for clicking on this! I hope you can help me out with my betta buddy, Dice. Here's some info!

What is the water volume of the tank? 10 gallons
How long has the tank been running? approx. four weeks
Does it have a filter? Yes, mini bacto-surge sponge filter
Does it have a heater? Yes, 50 watt aqueon submersible aquarium heater
What is the water temperature? 76-78 degrees fahrenheit
What is the entire stocking of this tank? One emerald cory, two julii corys, one peppered (?) cory, and three harlequin rasboras
Some extras: I have three marimo moss balls and an eco-bio stone/block


How often do you change the water? Once or twice per week, depending on ammonia levels
How much of the water do you change? Approx. 1/3
What do you use to treat your water? API quick start and API stress coat
Do you vacuum the substrate or just the water? substrate and water


Did you cycle your tank before adding fish? No :/ Unfortunately I didn't know about cycling tanks until I already had fish.
What do you use to test the water? API freshwater master test kit

What are your parameters?
Ammonia: 0.25 ppm
Nitrite: 0 ppm
Nitrate: 0 ppm
pH: 7.4


How often do you feed your fish? One or two small meals per day
How much do you feed your fish? Small amounts for all but the bottom feeders. Since I have four of them, I tend to put two pellets down every time they run out, as I'm gone most of the day/night and can't ensure they won't have other food.
What brand of food do you feed your fish? Fluval bug bites the most frequently, followed by new life spectrum small fish formula every so often, and omega one shrimp pellets for my bottom feeders.
Do you feed frozen or freeze-dried foods? No. I've been planning on getting freeze dried bloodworms, but haven't yet gotten around to it.

Illness & Symptoms:

How long have you had this fish? Approx. four+ weeks
How long ago did you first notice these symptoms? 14 or so hours ago
In a few words, can you explain the symptoms? Discoloring along belly and missing/torn fins where discolored patch is.
Have you started any treatment for the illness? Methylene blue dip
Was your fish physically ill or injured upon purchase? As far as my unknowledgeable self was, no. But he had been stuck in a tiny betta cup from petco for at least two weeks (it's why I purchased him initially- I didn't like to see this poor guy there for so long)
How has its behavior and appearance changed, if at all? Seems to be hiding a bit more, but is still actively roaming the tank and eating well.

Explain your emergency situation in detail.

Thank you for reading this far! Here's some more info: So from the beginning, I originally purchased my little betta friend (his name is dice!) a few weeks ago. He had been in a small betta cup for a minimum of two weeks, and I felt bad for the poor guy so I impulsively bought him and got him all set up in a 10 gallon tank at home. I didn't cycle the tank, as this is my first fish since I was a kid and I didn't know enough to do so. The first two weeks were definitely full of constant water changes and worry for my little guy! A few days in, he tore off his top fin on one of the hideaways in my tank, but that object has long since been removed! One my water seemed to stabilize a bit, I got two julii corys and one peppered (?) cory. Cut to a few more weeks later, and I added an emerald cory and six harelquin rasboras. The harleys (as I've taken to calling them) were new to the store, so I anticipated some of them dying. And of course, one died and one seemed to have gotten his tail fin munched off? that one died as well, sadly. One disappeared entirely, and I believe my betta may have eaten it! I did a full sweep of the tank, took everything out, etc. and still couldn't find the third one. The remaining three seem to be doing just fine though, despite my prior worries of them being too stressed without enough friends. Cut to a few days later, and dice has this odd discolored patch and ravaged fin! I'm not sure what it is at this point- did he get burned from the heater? stuck in a plant? (I have fake plants, but he's been swimming through and around them just fine until today). At this point, I'm not really sure what my next step should be. I just hope that he'll be okay! My other fish are doing perfectly fine, active and content. But little Dice can't seem to catch a break.

Thank you so much for reading!! And I hope the information provided is at least somewhat helpful. Please let me know if there's any more information I should include, or if there's anything that doesn't make sense or is confusing. I've attached some pictures of Dice, although they are a bit blurry due to the quality of my phone's camera in this lighting. Thank you again!!


Good luck I don’t know much about betta and I have never in my life seen that on any fish.


He’s probably nipping at his fins because of stress.
My guess is he has columnaris which will need to be treated. It can kill fast. The tank also has a few stocking problems. The corys need to be in schools of 6 (and those 6 should all be one species) and the rasboras may be stressing the betta. If you rehome the corys and add in more decor plus treat for columnaris I think you’ll be able to fix your problems.


The ammonia might also be stressing him out. I’m not an expert, but there is a bit of debate of which the ammonia should be a 0 or 0.25 ppm. You should probably make sure your ammonia doesn’t elevate.

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