Endler came with white something on tail, should I worry?

[Anubias Banana]

Key information:

1. white -something, looks like a !
2. came from the LFS like this yesterday, must have had whatever it is when in the fish shop
3. no change in 24 hrs
4. I didn't pick the fish out individually the guy just scooped a random 5 out of a tank of lots of them
5. If there were others in the tank at fish shop with white patches I didn't notice
6. there were no dead fish in the tank at LFS
7. our tank is new but has been precycled, 0 ammonia and nitrite as of yesterday when the fish were introduced but then see also 2.
8. fish in question is active and eating, behaviour is indistinguishable from the other 4 endlers

Anyone care to propose a diagnosis? Have advice? Could it just be a genetic marking?

 

[FriendlyGeek]

I'm no expert by any means but to my untrained eye, that looks like the natural markings of the fish (assuming you mean the small white part on the bottom half of the tail?)
He's a very pretty little fish

 

[Colin_T]

There's two white things there and they could be calcium deposits in the fin rays or excess mucous. I would need to see better pictures from different angles to make a more positive ID but I doubt it's anything to worry about. If you're concerned, you can add some salt but I would give it a few days and see how it looks then. If it gets worse, post more pictures asap.

 

[Anubias Banana]

Thanks, to you both, I am hoping it's just a natural variation and the new-fish paranoia, will continue to monitor and update if there's any change.
@Colin_T Never had to use salt in a tank before, is there a brand you'd recommend over others?
@FriendlyGeek thanks, they are a handsome bunch of lads.

 

[Colin_T]

Any sort of non-iodised sodium chloride can be used.

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 1 to 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 (2 litres or half a gallon) of tank water 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.

 

[emeraldking]

It's a bit hard to tell from this photo. But it does happen frequently in black bar endlers (of mixed origin) that they show spots like this in their fins as a marking. In that case, no worries.