New Panda Cory Flashing

Hi just got this little fella from the LFS today and noticed him flashing once or twice this afternoon. Doesn’t look like ick but is this a fungal infection due to injury?
He’s otherwise active and inquisitive at the moment in my 7 gallon planted tank with two oto and two other pandas.
Water tested 0 ammonia and 0 nitrite.

Is there anything that I can do to help or should wait and see?

Stress is probably an issue here. Pandas are schooling fish. They should be in a group of at least six conspecifics. More is better.

Hello. Corydoras shouldn't be kept in small tanks. There are some species that will tolerate changes in their water chemistry, but this isn't one of them. The smallest tank is probably 20 gallons. But, I've never kept them in a tank less than 30 gallons. The more water you have your fish in the better for their general health. You should be removing and replacing half the tank water every two to three days to keep the water livable for fish in such a small tank.

10

Can you measure your nitrates?
I had a flashing problem with my Corys and Roseline Sharks that was related to the nitrates being too high. The Roseline Sharks would start to flash if the nitrates went over 20-30 ppm. When I eliminated the nitrates, their flashing went away.

When my pandas were flashing I treated for fluke worms and it cleared things up, if he has something like that you'll need to treat the whole tank as you've not been able to quarantine. It may be the change in parameters from the store, do you know your gH and kH? 7 g is quite small for what you have, I know others have said you need a bigger group but you ideally need a larger tank first, with a sand substrate for your cories, once you've worked out what the problem is.

7 gallon? Typo?

It's not fungus.

It could be the start of velvet, white spot or another external protozoan parasite like Costia, Chilodonella or Trichodina. These last 3 protozoa cause the fish to rub on objects, develop cream, white or grey patches on their body, and in extreme cases, the skin bleeds around the edge of the cream, white or grey patches.

White spot appears as small white dots that resemble grains of salt, sprinkled over the body and fins.

Velvet appears as a yellow/ gold sheen over the body.

External protozoan infections on fish can be treated with copper or Malachite Green. Salt can be used to treat Costia, Chilodonella and Trichodina but does not treat white spot or velvet. White spot and velvet can also be treated with heat (30C/ 86F) for 2 weeks. Heat doesn't affect the other protozoan infections.

At this stage I would wait a few days and see if any white dots appear on the fish's body or fins. If it does then jack the temperature up to 30C and keep it there for a week after all the white dots have gone.
If no white spots appear and the fish continue to rub on objects, add some salt, (see directions below).

---------------------

SALT
You can add rock salt (often sold as aquarium salt), swimming pool salt, or any non iodised salt (sodium chloride) to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres (5 gallons) of water. If there is no improvement after 48 hours you can double that dose rate so there is 2 heaped tablespoons of salt per 20 litres.

Keep the salt level like this for 2 weeks.

The salt will not affect the beneficial filter bacteria, fish, plants, shrimp or snails.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

If you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.

When you first add salt, add the salt to a small bucket of tank water (about 2 litres/ 1/2 gallon) and dissolve the salt. Then slowly pour the salt water into the tank near the filter outlet. Add the salt over a couple of minutes.

Thanks everyone, he’s stopped flashing and is actively exploring his surroundings with the other two. They are in the smaller tank on the left which was set up for guppy fries but I (probably unwisely) decided to put get some more fish to get some nitrates for the plants. It’s currently reading 0 ammonia, 0 nitrites and somewhere between 0 to 5ppm for nitrates.

I’ll keep them there for a fortnight as a pseudo quarantine thing and then move them over to the main tank on the right where there’s five orange corys, five guppies and two otos. A bit crowded with the three in there but i’ve got ample filtration with a fluval c4 i believe. Can’t do much about the substrate at this point but am thinking of getting more otos. We had six but two died and two were transferred to the smaller tank because there wasn’t enough algae for four and they won’t eat peas or algae wafers.