brackish water setup

I have been thinking about getting Colombian cat fish shark to put into a new tank that I'm buying, however having read up on them it sounds like they don't do well in fresh water and instead prefer brackish water?
So, hat can you tell me about brackish water setups? What issues would one expect when setting up / maintaining a brackish setup?

Is there any differences in equipment required?

The equipment you will need for a brackish water tank is similar to a freshwater tank but with a few additions. You will need:

Aquarium. Some articles claim that a 55 gallon or larger aquarium is required for brackish water aquaria but this is untrue. You could go as low as a 10g or even a 5.5g. The recommended set-ups later in the article may help you chose tank size.
Filter. The best filters for a brackish tank are hang on the back mechanical and bio-wheel filters or canister filters. Undergravel filters will not work properly with a sand substrate. For aquariums larger than 20 gallons, you should use 2 filters on opposite sides of the tank. You will want to have your water turned around 10 times per hour (so you would need a single 300gph filter or two 150gph filters for a 30g tank).
Heater. Never go cheap on a heater. Submersible heaters are much better at spreading heat and are less likely to shatter. Make sure you get a heater marked for fresh AND saltwater use. You also need to make sure the heater is adequate in size. A rule of thumb is 5 watts of heat per gallon.
Glass Top/Light Hood. All tanks should be covered and brackish tanks are no exception. Keep in mind, also, that brackish water evaporates faster than fresh water. If you plan on keeping plants, get atleast 1.5 Watts of light per gallon of water.
Thermometer and Hydrometer. You will need the thermometer to keep the temperature and a hydrometer to measure the salinity of the water. A cheap swing handle hydrometer is fine for this situation.
Substrate. Brackish water areas always are covered in a sandy, silty, or muddy material and I feel that sand is the best option for a brackish water aquarium. You could use marine aragonite, "Minerial Mud", or play sand (which can be found VERY cheap at hardware and home improvement stores). If you plan on keeping live rooted plants, you will need about a 1" layer of substrate (avoid larger layers as they can build up anaerobic spots) and for a fish only tank, a very thin layer is best.
Marine Salt. I prefer Instant Ocean but most brands should work. AVOID Freshwater Aquarium Salt as this is not the proper salt to use in brackish or marine tanks (although it is fine in full freshwater tanks to fight off parasites).
Water Condtioner. As with all aquariums, you will need a product to remove chlorine and chloramine from your tap water before placing it in the tank. Make sure the product is listed for both fresh and saltwater use.

Thank you for the information.
I'm not completely sure that I'll be going ahead with this setup at this stage, but I definitely will in the future!
Just need to research what other species I could keep with the Columbia Catfish Sharks!

I am also planning on trying to breed bamboo shrimp at some stage, they also require brackish water for breeding, but from what I've seen of the catfish, the shrimp wouldn't last 30 seconds in the same tank!

It'll be a 100 litre tank that I'll be using for keeping them, so its definitely plenty big!
The lighting is something I'll decide upon later along with plants etc (live or artificial)

Lots more reading and researching to be done

Great info from jeff about heater. I forgot the heater on first brackish tank, never made mistake second time.have to get mono fish and maybe archer fish as well to go with sharks .get them all young in fresh water gradually bring them up to brackish,monos grow slow they eventually need marine tank why other two prefer brackish.When the monos grow big you will never get rid of them great fish and u will end up putting them in their own tank.jUst to add if you go for scats as well they eventually school together with monos.

Just correcting myself I think not 100 per cent someone may answer but the columbian sharks can go marine also so
Leave archers out

No probs it is a different setup and for sure one of the best and your right to do lots of research before wasting hard earned cash for it not to work

Bamboo shrimp are cool but not with catfish only thing good out of that is you will be able to hand feed them, haha

Keep us posted if you do decide to go for it in the future because it would make a great post on a start to finish project

badmanstropicalfish.com/brackish/brackish.html
www.drsfostersmith.com/pic/article.cfm?aid=844

Great info.... exactly the information I was looking for!