Ok I'm going to start off by saying that if you wish to get into discus I highly recommend you try keeping some German blue rams first. Their tolerance for poor water quality is very much close to discus. This will help you to see if your up for the challenge.
Discus are not very difficult, and can be kept by the novice fish keeper as long as a few requirements are met.
First lets address water changes. To keep them healthy your normal schedule of 25% a month will simply not do. 25% every other week will simply not do. Normally when you purchase discus you get young fish. For these guys to grow properly they will require 2-3 large water changes a week, but smaller daily ones are much better. But they can get by on large ones 2-3 times a week. If you do not do this your discus will not grow properly. They will become stunted and their lives will be severely shortened.
The water changes are needed for several reasons. Discus are intolerant to less than pristine water conditions, so right off the bat large frequent water changes are needed. It is long believed that the discus themselves produce a growth inhibiting hormone. This is thought to hinder the growth of the other discus helping the strongest in the tank survive. When young in order to feel comfortable discus need to be kept in large groups, just as if they were a schooling fish need to be in a group of at least 6 fish. They have to be fed 2-3 times a day, this contributes to the water quality going down hill faster than your average community tank. Water changes are the only way to deal with these problems.
Once they become adults you can get by with only doing a 50% water change every week. But this still goes back to my post about nitrates. Every now and then you will need to do several 50% changes in a weeks time to get the nitrate levels down.
Not doing these water changes
WILL result in 1 of 2 things. Sick or dead fish. This is not my opinion but is a FACT.
Adding more filters isn't going to help you skimp on these water changes. All that will do is remove more crap from the tank, but the crap is still in the system as it is now just in the filter instead of the tank. Also wile adequate filtration is a must discus do not like loads of current so over doing it can be detrimental. DO NOT USE AN UGF with discus. The chance for a poor water quality is just too much of a risk when using this method of filtration.
With a little thought put into your aquascaping bare bottomed tanks are not ugly. IMHO I wouldn't call my bare bottomed discus tank ugly.
The reason for keeping them bare bottomed again directly relates to water quality. Having gravel makes keeping the tank clean more difficult. It is next to impossible to get all the mulm out of the gravel, wile having the tank bare bottomed you get to see where the poo is so it can be completely removed with your water changes.
Real plants are preferred over fake ones. As they will help keep your water quality up. And your nitrates down. But for this to help you have to pick some plants that will actually use the nitrates faster than they are produced. Most low light plants are slow growers so they offer very little help in this department. Hornwort on the other hand is a very fast growing low light plant that will act like a nitrate sponge.
Discus do like warmer waters than most other tropical fish. Any where between 82-86 is an ideal range for them. This can be accomplished with one heater but in a 55 gal your going to be safer to have 2 smaller heaters. This is because running the tank at these temps is going to put a strain on any one heater and when and if it goes bad chances are it will stick in the on position thus cooking your fish. Having 2 smaller ones means that if this happens the one heater will not have enough power alone to cook your expensive investment.
You mentioned that an UGF is going to be needed for added O2. This is not exactly true. Due to their sensitive nature to water quality. You can not stock the tank like you would a common community tank. This means that there will be plenty of O2 for what fish are in the tank.
Further more discus are
not community fish. This is for several reasons. 1 They tend to be very shy and skittish so boisterous tank mates can and will often spook them to the point that they refuse to eat. Then they are doomed to slowly starve. They will not eat just because they are hungry if they are stressed. 2. Their temperature requirements are not going to be healthy for most tropical fish, and will eventually lead the other residents’ demise if kept at these temps long term. 3. Discus are not aggressive eaters and if kept with tank mates that are, chances are good that the discus will not get enough food.
Now this doesn’t mean you can’t keep other fish with discus. It just means you have to choose the tank mates carefully. You have to build the tank and the inhabitants around the needs of the discus.
Tetras like rummy nose, and cardinals are both good choices. Also you can keep some species of pleco with them. With the plecos you have to be careful and keep an eye on them. If the plecos food requirements are not met they will often resort to sucking on the discus’s slime coat. This will stress the discus and can kill them. Blue rams are another good tank mate, as are some species of corie.
You can tell if they are adults simply by their size. An adult can reach lengths of 6-7 inches without the tail. In my tank you can see an example of a sub adult, and my wild discus is full-grown at 7 inches.
LOL No they do not attack humans. I almost choked on my coffee when I read that one..LMAO!!!!
Ok as far as your choice for a vendor. Emm the fish I have seen come from them are often way over priced stunted, hormoned, Asian imports. Sadly a lot of them should have been culled and never sold to the public. Buying discus can be a tricky affair. I would not pay more than 30 bucks for most juveniles, but you have to be careful whom you buy them from. Sadly a lot of commercial vendors will over charge you for crap fish. Your best option is going to be to find a good breeder on aquabid and buy from them. If you have any questions about any particular seller I will be more than happy to tell you if they are on the up and up.