Thats fair. I admit I seem to have responded pretty roughly there.
I'll rephrase, I wouldn't put fish in a tank of that size, and I'd certainly disagree with a poster above saying you can fit several.
Also, OP, you are adjusting your clean up crew trying to fit a fish. Hermits, snails etc, they don't really add to the bio load a tank can handle. The only problem you may have is that there isn't enough algae and detritus for them to eat and they die. Your original CUC was fine. Taking the hermits away to add a clown goby really won't work.
I'll stand by my original suggestion in your other post. Look into getting a mini carpet anemone and a pair of sexy shrimp, they are small, and will look great as center pieces in a tank of that size.
If you really insist on getting fish, upgrade to a 10 gallon tank, they are cheap, and the equipment wont' run you much more than what you'll have on that 3 gallon. Any reason you are trying such a small tank?