What size is your tank? 10 gallons
What temperature is your tank? 78-80 degrees
Does your tank have a filter? yes
Does your tank have an air stone or other type of aeration? no
Is your tank heated? yes
What tank mates does your betta fish live with? african dwarf frog, snail, neon tetras, red cherry shrimp
What type of food do you feed your betta fish? flakes, blood worms, sometimes mysis shrimp and beefheart
How often do you feed your betta fish? once a day
How often do you perform a water change? once or twice a month
What percentage of the water do you change when you perform a water change? 25-40%
What type of additives do you add to the water when you perform a water change? Prime
Have you tested your water? If so, what are the following parameters?
Alkalinity: 80 KH
Symptoms and Treatment
How has your betta fish's appearance changed? dark growth
How has your betta fish's behavior changed? none
When did you start noticing the symptoms? one or two months ago
Have you started treating your fish? If so, how? no
Does your fish have any history of being ill? no
How old is your fish (approximately)?1.5 years
First, I know I probably need to be doing more water changes because of the higher bioload and slightly high nitrates, I am starting now!
A month or two ago I started noticing a dark spot on the left upper side of my betta's body, under the front of the dorsal fin. At first I thought this might be a natural color change starting, but then the spot also starting bulging out. The area has continued to grow. This is only visible on the left side of his body. The area is a darker color and bulging out, like a growth or tumor inside his body. I couldn't get a picture of this but when lit well from behind, when his entire body is somewhat translucent, the entire area of the dark bulge is black and not transparent, when the rest of his body is. Here are the pictures I could get:
I have read about lots of different fish diseases and ailments, googled, and searched the forum but have no clue what this could be. His behavior hasn't changed and he is eating well. Nothing else has changed. He did tear a fin recently but it is healing well. The only thing I can imagine is this is some mysterious tumor. I was thinking maybe infection from injury, but he has been going strong for a couple months now. Should I just go ahead and quarantine him or might this be something totally benign and it would only be stressful?
I'm hoping someone more well-versed might recognize this and have recommendations for treatment, but if anyone at all has any guesses I would love to hear them!