brackish (low water) cycling

The bacteria are different as the water changes to saltwater. So, cycling for FW won't work--unless you will be getting the skippers in FW and converting them. If they are coming in BW, you need to cycle the tank with BW, and then add. No test fish are needed--add ammonia, and test in 24 hours! This will provide better proof than any fish survival.

The changeover in bacterial species from FW to SW seems to occur about 1.012 very roughly. Below that the predominant species of nitrification bacteria are those from FW, above that the SW species predominate. If you cycle FW and then raise the specific gravity no more than +0.002 per week, the bacteria will adjust, the FW species will recede and the SW species will develop (effectively a fishy cycle, but without detectable ammonia or nitrite during the transition).

Since you are staying at low to almost mid-BW densities, you should have no issues with FW cycling, but either do so fishlessly or do FW and increase the density gradually (as noted in the first paragraph) to avoid problems. Mollies will hold the cycle during the density increases quite well. Then you can pull the mollies and introduce your target BW fish without problems.

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It's been a harder road travelled than I could of imagined fish. My mangal paludarium in which im housing mudskippers has been cycling for quite some time now and it's still not safe IMHO for my skips. I haven't even thought about ordering them yet.

I'd suggest just getting a master test kit and keep a log on whats going on and when. That's what I unfortunately didn't do, that I have recently started. By the way, you want to go the freshwater test kit for brackish, not the salt.

Let me know how it goes!


Oh, and I introduced ghost shrimp and clams the 2nd day it was set up. I figured I could use them and food to add ammonia and get a jump start rather than having "test" fish.