My male Zebra Danio has some strange looking lump or growth on his lower lip. He's so small I have a problem seeing it properly even with a magnifying glass so I will try my best to describe it. Here are the details:
1. Tank size: 140 L
2. Water parameters and brand of test kit used:
These are the parameters for the main tank.
We use the API Master Testkit and for gH Tetra gH kit.
3. Is your aquarium set up freshwater or brackish water?
4. How long the aquarium has been set up?
The aquarium has been set up for almost 3 years
5. What fish do you have? How many are in your tank? How big are they? How long have you had them?
3 Danios (one male about 10 months, about 3cm (= 1.2 inches) + tail; and 2 females about 10 months, about 3cm (= 1.2") + tail; 4 corydoras (two males almost 3 years and about 3.5 cm (= 1.4") + tail and 2 females about 9 months one about 3.5 cm (= 1.4") + tail) and the other one 6 cm ( 2,4 ") + tail, and two Oto Cincluses (male and female about 17 months, male is about 2.5 cm (= 1") and female 3.5 cm (= 1.4")) - Those times are how long we've had them. No new additions since these ones.
6. Were the fish placed under quarantine period (minus the first batch from the point wherein the tank is ready to accommodate the inhabitants)?
No. We have put new fish straight in the main tank, but we've decided that any new fish in the future will be put in quarantine first and at the moment I've had two small, new, female zebra danios in a quarantine tank for 1.5 weeks. The last addition was about 9 months ago.
7. What temperature is the tank water currently?
24 Celsius (= 73.4 F)
8. Are there live plants in the aquarium?
There are 5 live plants that have been there over 1.5 years, and one of them was put there about a 4 months ago.
9. What filter are you using? State brand, maintenance routine and power capacity.
We have an Eheim Aquaball 2210 filter. We clean the pads in tank water during water change once a week. 550 L per hour (=145 US Gallons per hour).
10. Any other equipment used (aside from heater and filter which are two very important components of the tank)?
No other equipment
11. Does your aquarium receive natural sunlight at any given part of the day? What is your lighting schedule (assuming you do not rely on sunlight for our viewing pleasure)?
The tank rarely gets natural sunlight, but if we get some sunlight, it's in the morning. Usually we keep the curtain so that the tank doesn't get too much sunlight. Automated lighting in the tank is on from 11.30am to 9.30pm. We live in Finland and at the moment there is no dark night at all. It's the lightest time of the year and it's light outside 24 hours a day so the house doesn't get very dark either, even with the curtains closed.
12. When did you perform your last water change and how much water was changed? How often do you change your water? Do you vacuum the substrate?
Last 30% water change was 2 days ago and the next one will be in 5 days.
Our normal water change is about 30% once a week with a gravel hoover at the same time. The filter is cleaned in the tank water every time as the plants produce quite a bit of dead material.
13. What foods do you provide your fish? What is the feeding schedule?
Our fish get meals at 9am and 9pm. They get flakes, granule foods, and we have three different types of pellets for the bottom feeders. Twice a week they get frozen lobster eggs instead of dry food in the morning. We also put a slice of zucchini or cucumber for the otos once a day.
14. What unusual signs have you observed in your fish?
I noticed this morning that the male zebra danio, Marco has this strange looking lump on his lower lip. It looks like the lip is swallen. When you look at it from the front it looks a little darker, maybe not totally black, but close to it. When you look at it from the side, it look fluffy and almost see-through. So I can't tell 100% sure even what color it is as it looks different from different sides. I will put pictures lower down. This lump is the only symptom on the fish. He ate normally this morning, he's chased the girls and is very active as usually. I don't see anything else unusual. I have looked at him and his lump with a magnifying glass, but don't see anything more. I do this magnifying glass health check daily always to the danios, and to the corydoras when they happen to be suitably around. Corys have never been sick.
Almost 2 weeks ago one female leopard danio died probably of being egg bound. After this, this male danio was bullying the other two females danios so much that we purchased two female zebra danios and put them in quarantine so that they would balance the situation in the tank. We've had so many times protozoan come with new fish that I treated them with metronidazole in their food for 10 days, today being the last day.
15. Have you treated your fish ahead of diagnosis? If so, what treatments did you use? State your reasons for planning ahead of proper diagnosis.
I have not given any medications to the main tank. I have wondered if it would be mouth rot, but as there are other options, I wanted to be sure about the diagnosis before treatment. For Mouth rot/fungus (columnaris), I have available Furanol 2 by JBL at home with the active ingredient of Sodium Nifurstyrenat 20mg. But as said nothing has been given yet.
Also if this fish would need to go in a hospital tank, I would need to move the new fish in the main tank. I have only two tanks.
Advice on what this could be would be much appreciated. Thank you!