Redevilz

Awesome, just awesome

Welcome to the world of marine!!

Firstly you need to choose if you would like to use a sump or not. A sump is another tank (as big as you fit under the tank) that is connected to the main tank via pipe and pump... You can put the equipment in the sump so you cannot see it. Not only does having a sump add water to your system; therefore being more stable but it also looks better. I strongly recommend a sump.

You will need heaters, a protein skimmer, lighting and wavemakers.

Choosing livestock:

The corals that you can keep depends on the brightness/quality of your lights and the power of your wavemakers. If this is your first marine tank I would recommend Xenia, hammer corals, torch corals, bubble corals, corallimorphs, zoos and toadstools.

Some of the nicer easy to keep fish include Bangaii cardinals, ocellaris and percula clownfish, pyjama cardinals, blue tangs, coral beauty angelfish, most blennies and gobies.

Be careful of some Angelfish as some varieties will eat corals.

Filling your tank:

You have 3 options of where you get your water from to fill your tank. You can either use tap water and just add salt that you buy (you need to add the right amount otherwise fish and corals can die. Another option is to collect water from the ocean (further offshore the better). Or the best option which is to get premixed and already has good bacteria and the right salt level from a local fish store.

Use fine coral sand for the gravel

I strongly recommend you get test kits for ammonia, nitrate, nitrite, calcium, phosphate, pH, kH and salinity.

These are what the parameters should be:
pH 8.0-8.4
Ammonia 0
Phosphate 0
Nitrate 0
Nitrite 0
kH 8-13
Calcium 350-500 depending on what corals you are keeping.
Salinity 1.020-1.025

Feel free to ask more questions.

Cheers and goodluck

Where's the best place to catch Geophagus Brasilliensis? And which rigs and bait are the best to use?

Cheers

Was it the same evil 'big catfish' in the first and third scenario?

Are they swimming normally?

I had a green terror with similar problems, not eating, swelling around the anal area and staying to the bottom. The green terror struggled to swim straight, spiraling around after a day of the swelling, hopefully that doesn't happen to you.

Goodluck