Salinity for Killifish

Hi,

I know that you are supposed to use non-iodized table salt to ward off velvet disease in killis, but I cant' find any non-iodized salt in my area. I do have some salt from my marine tank, but I don't think that 1tsp per 4 litres of marine salt will give the same salinity as it would with the same dosage of table salt.
Does anyone know what salinity the killis need so that I can measure it with the hydrometer rather than guess and risk the fish?

 

Hi there

There is some difference between table salt and your marine salt - namely that table salt has been iodized, and that the marine salt has other compounds in it to adjust other chemical parameters in the water, such as pH.

I don't see any reason why the marine salt and the table salt would give you different readings - they'll both mostly break down into Na+ and Cl- ions.

If you need to, just use the marine salt. Iodized table salt isn't safe for (living) fish.

Back to the real point - why are you adding salt to your tank? Yes, salt may ward off certain diseases such as velvet, but it also adds unnecessary stress to your fish. I'd only advice using salt as a treatment for disease, and for a minimal period only to limit the stress you place on the fish's body.

 

To answer your question, I was going to add salt to the tank because the sites that I checked out during my research suggested it, although that might be because other country's water contains different substances to ours.
You're (according to the websites) supposed to add 1 tsp per 4-10 litres as the killi fry are very susceptible to velvet.
I am not disregarding your advice, but if I can't use salt to prevent the disease in the fry (which are more difficult to see symptoms in) then what do you recommend?

 

Having no experience in breeding killis of any sort, I can't help you there. Hopefully someone will come around soon and help you on this point - the site gets a lot more visits during the week.

 

I would say 1 teaspoon per 10L is a maximum. Use the marine salt or any coarse bag salt you can get at a LFS. While the fry are growing out in the 2L tubs there shouldnt be a need to add salt as long as you use a syringe to suck up BBS with the saltwater they were hatched in for feeding. Salt is only for Notho's and not all Killi's. Salt will help to avoid velvet outbreaks but clean water is a much bigger factor. I have no idea what that salinity would be with a hydrometer but there is no exact concentration of salt needed.