im setting up a small pico reef,

with:

1. 30w heater,
2.small power head,
3.HOB filter from 10 gallon (even though not the best to use in marine tanks)
4. fiji sand 5-7 IBS
5.fiji live rock 3-5 IBS
6. a few hard corals, 2-3
7. maybe an annenome thing
8. correct lighting 30W 50/50 10,000K
9.inverts crabs, shrimps

But what i really want to know is, is there ANY fish just one, that i could keep in there. i know the tank is small and not very stable, but i have kept 8 tanks of all sizes for 5 years, and i have been known to have "perfect water", so please if you can think of any fish i could have please list it below.

I have a 55gal Salt water setup. Live rock and sand, Anemones, Shrimp, Em. crabs, and turbo snails. Up until a few days ago I also had a tank full of fish (about 10) clown fish, tangs, angel fish… A week ago my largest tang (5") jumped out of the tank twice in 12hrs. Then it disappeared. Now I’m down to 2 fish, a yellow tang (3") and a nesso tang(4"), and they’re both skiddish but fight over the food. All of the other life forms are still alive and the water checks out fine. Would a mantis shrimp go after only the fish and not the shrimp, crabs…? And how big would a manit shrimp have to bee to decamate my tank in less than a week? What’s getting my fish?

Will any of these fishes try eat a blood red fire shrimp, hermit crabs, star fish, or clams?

Magnificent Foxface
Copperband Butterflyfish
Raccoon Butterflyfish
Teardrop Butterflyfish
Falcula Butterflyfish
Golden Semilarvatus Butterflyfish
Blue/Green Reef Chromis
Ocellaris Clownfish
Green Mandarin Goby
Spotted Mandarin Goby
Yellow Tang
Blue Hippo Tang
Six Line Wrasse
Longfin Fairy Wrasse

I know the butterflys will try to eat the corals so doing a reef tank will be out of the question. Really want to do a reef tank but can’t have the butterfly eating at my money through corals. Also are all these fishes compatible with each other…I’m planning on having at least a 200 gallon setup.
Are there any corals that I may be able to have in the tank despite the butterflys?

I am planning on getting a 30 gallon saltwater aquarium with a power filter, skimmer, heater, ect. I am aware of all the items needed for a saltwater setup. I know that you dont need RO water for a Fish only setup, or most FOWLR setups. I know it is needed for a reef setup. This is all the info I can gather from many websites and a few books. Can I use a conditioner to remove heavy metals, chlorine, chloramine, ect. from the tap water, then add a good salt mix (instant ocean), then age the water and add to tank during water changes, or set up. I know to use conditioned freshwater for top off. Will the conditioned tap water be safe for invertebrates such as cleaner shrimp, hermit crabs, emerald crabs. I know you need it for corals but I cant find info telling me if I need the RO water for inverts such as shrimp or crabs?

ok, i have a 55gal reef tank, and it has been setup for about a month, and has 60lbs of fully cured liverock…my ammonia, nitrites are at 0 and my nitrates are at 5 or less…i was just wonding if you all think its fully cycled and ready for a fully cleanup crew

for that past 3 weeks i have had 5 snails and 5 crabs in the tank, everything is good but one hermit crab died somehow….he was unactive since the day i got him anyways….but no excuse….also i have 2 blue damels in the tank for over a week now and they seem very active and eat a lot…..advice? thanks.