Question about floaters and topping off the tank

[JoeG]

Is there any concern with topping the tank off with distilled water while there are still some floaters in the tank? Is there any data that suggests a higher salinity is beneficial to the developing larvae or the newly morphed fry in regards to surviving?

[Dch48]

There is a higher survival rate at higher salinities but as long as it doesn't drop below 1.010 it should be fine.

[JoeG]

Thanks for the reply. The tank is at 1.012 when full. It is a 5 gal tank and the level is down about a 1/4” from the full level. I usually top off when the level reaches about 1/2” from full. There are still four floaters out of the 35 that were released on October 23. The other 31 babies are swimming around, climbing the side walls, and are walking around on the lava rocks. That’s why I was afraid to top it off because they are very active right now. My first batch of 15 fry were released around September 23 and I have only seen about 3 that have since developed into juveniles and I haven’t seen them for a couple weeks. I know that I topped it off when they were still floating or just becoming free swimming. I am hoping that more of this group will make it to become juveniles.

[Mustafa]

Simple topping off that does not change the salinity much should not be an issue. But I'd do it slowly....maybe over a whole day. Just fill in a bit of water every time you walk by the tank.