So many opinion.
Just as I said before, I can drop discus and just go with Silver Dollars. Cheaper anyway and less maintenance. I am still on the fence about it because as I said before I talked to people that are very experienced discus owners that have fully grown Discus in 55 gallon tanks, but not a lot. So I don't know!
No matter what anyone says a bigger tank is going to always be better regardless of what fish you put into it.
As far as the Tangs go, I am in some disagreement with even that! There has been studies that have proven that some Tangs do well in an environment that some hobbyist wouldn't even consider. They concluded that Tangs in a smaller tank vs Tangs in a larger tank are about the same in terms of growth and stress levels. Meaning it's all about the swim space vs the tank size, but they also agree you don't want to keep a Tang in a very small tank. Most people would assume a 100 gallon tank is to small for a Yellow Tang, but many websites and experts say that it's just what they need.
Jay Hemdal Live: Beware the Tang Police!
Arrested by the Tang Police: I Refuse to Confess! | Coral Magazine
I am also in disagreement about the 50 gallon PER FISH as that is not the way of looking at tank a minimal.
Tank Minimal is what the animal would need in order to live comfortably with enough swim space. So if I were to add 4 discus in the 50 gallon tank without anything to obstruct their swim space, they would be fine. Now if we start adding decorations and plants your swim space gets less and less. Thus you would need a slightly larger tank to make up for the lost swim space. So a 55 would allow for the make up of lose swim space if I were to space out the plants and decorations accordingly. Adding three more Discus would take up very minimal swim space for the animal and has no effect in swim space as they can simply move out of one another way, or swim together. Plus being Discus are a social fish, it would only increase their health as only having one would not be healthy for the animal at all.
All in all, I agree with one article. If your fish has shown no sign of stress and is eating and swimming accordingly and it lives as long as it's counterparts in the wild, than how can we know for sure your fish is not happy? As hobbyist it is our job to give our fish the best possible environment money can afford, but I also believe some people lose sight of what is good for the animal and only go for what would make themselves happy. If a bigger tanks makes you happy, then go for it.
Many people have told me Discus are fine in a 55 for their full life of 10 or so years. I have known people with Discus in a 55 that have kept them successfully with them fully grown and happy and healthy looking. So in reality would four of them in a 55 be unhealthy for them? So much evidence form my end says no and in fact is just what the doctor ordered for only a SMALL community of them.
Right now I have two Tangs in a 55 gallon tank. I have a Yellow Tang, and a Yellow Eye Tang. I bought the fish to get them out of the small tank the other owner had them in (20 gallon). I rescued the poor Tang that was nipped to hell, and his poor fins were almost gone. In my 55 gallon he has grown bigger, stronger, and ALL of his fins are grown back. If my Tang was stressed like SO many people say he would be, than explain the growth and the fins growing back. You need a happy fish in order for their fins to grow back. His fins were not grown back for many months because of the stressful tank environment he was in before, now he is one healthy good looking fish.
So is there tank requirements? OF COURSE there is! The example would be my Yellow Tang. He was not happy and not healthy in a 20 gallon tank. So there is minimal requirements and that is why they are in place. To keep idiots from buying poor fish that would end up being to BIG for the tank. Right now I am in the middle of doing a 120 gallon tank to get my Tangs into a bigger tank. That is why i am having a 55 opening up I want to do a freshwater in.
