What is this tiny bump on my new Platy?

[laurenb252]

Yesterday I bought two Platys from Pets at Home, and less than 24 hours later I’ve noticed this tiny, slightly raised bump below the mouth of one of them. I’ve attached a photo that shows it quite clearly.

Please can anyone advise me on what this might be? I’ve already rang up Pets at Home and they’ve said I can bring it back, but if it isn’t anything contagious then of course I don’t want to move it. I feel sorry for the poor thing, it’s really active and is eating well. It seems really happy in the tank, but of course I can’t risk infecting my other fish. Another thing to note, the bump doesn’t have a white appearance unless it’s under the light (like shown in the photo). When watching the fish in the tank, it’s not that easy to spot.

Just to be clear, I unfortunately don’t have a quarantine tank to put the Platy in. I’m usually at university most of the time so my parents wouldn’t want something else to monitor whilst I’m not at home.

 

[JemZ]

What are your water parameters and other fish?

 

[Colin_T]

It looks like excess mucous and there is some on top of the mouth too.

The fish also looks skinny in the back and that could be from lack of food or intestinal worms.
What does its poop look like?

What is the ammonia, nitrite, nitrate and pH of the tank water?

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I would do a water change and add salt.

You can add rock salt (often sold as aquarium salt), sea salt or swimming pool salt to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres 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.

If you only have livebearers (guppies, platies, swordtails, mollies), goldfish or rainbowfish in the tank you can double that dose rate, so you would add 2 heaped tablespoons per 20 litres and if there is no improvement after 48 hours, then increase it so there is a total of 4 heaped tablespoons of salt per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria but the higher dose rate (4 heaped tablespoons per 20 litres) will affect some plants and some snails. The lower dose rate (1-2 heaped tablespoons per 20 litres) will not affect 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.

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If it gets worse overnight, it could be Columnaris but I think it's just excess mucous. Monitor it and see how it looks in 24 hours.