Large unknown lump on side of fish

[imod001]

Hello. I've lurked on these forums for years now, first let me thank you for all the great advice I've read over the years.

I am having an issue with my Discus tank, the problem is not currently with one of the Discus in the tank, so please forgive me if it is inappropriate to ask for your help at this point. One of the tank mates has a large round lump protruding from its side, it looks as if it is under the scales. I am worried that this may affect the Discus in my tanks. I'll do my best to give you all the info you need, I've cut and pasted the question form concerning the disease, and have attached a clear as possible picture for you.

1. Please explain the problems with your fish. When did you notice the problems and did anything unusual happen that you think started them?

- A large lump on the side of a Von Rio Tetra, rather large. I just noticed today as the fish was swimming by. None of the other fish appear to have anything
similar on them.

2. Symptoms (i.e. turning dark, excess slime, not eating, clamped fins, flashing, darting, clamped gills, white/yellow/green poop, hiding, headstanding or tailstanding, white on tips of fins, rotting or fungus, blisters/white zits on fish, bloated, cloudy eyes, wounds).

- No odd behavior, the fish is acting just as it always has. Eats normal. Swims fine. Still shoaling/schooling with the other tetras.

3. What medications/ treatments have you already tried and what were the results. Include dosage and duration of treatment.

-No treats done at this time, cannot identify the problem at this moment.



Tank/Water

4. Tank size and ages, numbers and sizes of fish.

-125 gallon, running for slightly over 2 years. 15 tetras, serpae and von rio(24 months) 5 long fin Zebra Danios(23 months), 12 Striped Khuli's(23 months),
7 Oto's(22 months), 9 Bolivian Rams(21-22 months), 5 mix Thai Discus(18 months), a seemingly unending supply of trumpet snails and various types of shrimp.

5. Water change regime (What percentage and how often).
-50% once a week.

6. How long has tank been running? Is it bare bottom? If you have substrate, what type and how deep is it?
-Slightly over 2 years running. Eco-complete substrate, very heavily planted, ranging from 2 to 5 inches.

7. Do you age your water? If you do for how long and what is the ph swing.
- No water aging.

8. Parameters and water source;

Note: Water Parameters are important in diagnosing problems within a tank. If you don't own test kits for the following information, you can purchase them, test your parameters and post this info as soon as possible.


- temp 78.8

- ph 6.65

- ammonia reading ~0

- nitrite reading ~0

- nitrate reading 20ppm (planted tank, I fertilize regularly.)

What type of water or combinations of water sources do you use? If it is an RO/tap/well water mix, please list percentages in the mix.

- well water ____

- municipal water __X__

- RO water ____


9. Any new fish, plants or inverts added recently.

-No new fish or plants in the past 18 months.


10. Include any pictures or videos you have which shows the symptoms. If you can't add them to this post, please provide a link to them.
IMG_0126.jpg

[nc0gnet0]

Appears to be a tumor. I would cull the fish.