With all due respect to Aiken and his experience with this fish, I have been a commercial breeder of Angelfish breeding literally hundreds of pairs of them so I have a bit more insight into the fish and their personalities. There's a lot of personal opinions and experiences on the internet about tank size, gender characteristics and pairings which are just wrong, or at the best limited in success. So here's the facts:
Wild Angelfish are a schooling fish. Their insecurity is when they are alone. In that school there is a hierarchal society. There will always be a #1 top dog, a #2 then #3, then#4 etc. in a school. There is always fighting or aggression to determine who is #1 then #2 and so on. This aggression is generally not lethal but can lead to ripped fins, missing parts, etc. That's the nature of this fish. As Aiken said, they are not Angelic at all. They got the name from their appearance, not their personality.
Domesticated Angelfish ( which are most of the Angels on the market today) have been around for a long time and many generations from wild so many have lost that need to be in a school so keeping a single domestic Angel MAY be fine. Unfortunately, you won't know if it will be fine alone until it's in your tank alone. In your case, if the fish is eating, is not hiding and not being bullied by other fish in the tank, he/she should be fine alone. Regarding the amount in a 30 gallon tank, depending on what other fish are in the tank, raising small angels in a 30 is fine but if that is their permanent home as adults, you would need to either keep 1 or at least 3 of the same gender ( preferably all males) and there will be little room for other fish in the tank. The reason for this is the upkeep of the tank. Adult Angels will produce a good amount of waste so the filtering system will need to upgraded, the water changes more frequent and the foods more adapted towards adult fish which most other fish that you would keep with Angels will not eat or have problems eating which is why they would be better off alone or with just some scavengers. The reason for all males is because 2 females can pair up and spawn together and if they do, they will terrorize the rest of the tank. Males will not do this but just create the hierarchy. That changes when a female is present as the males will fight for breeding rights to the female.
Angelfish personalities are all over the place. Some are sweet and gentle. Some are nasty. Some are overly aggressive. The only way to half know what your fish is going to be is to observe them in the shop you plan on getting them from to see how they are behaving with the other fish in the tank. Bottom line, there is just no way of knowing absolutely what you are going to get with domestic Angelfish anymore. Even the external characteristics of the genders are no longer only found on the single gender. The only way to definitely sex an Angelfish today is by observing their breeding tubes which they do not show until they are ready to spawn ( lay eggs.)
As for the people in the store being seasoned aquarium keepers, that used to be the case but in today's trade, unfortunately, that's not always the case and that's coming from members on this site and others who have worked in the box and family owned stores as well as myself who also worked in a number of Mom & Pop shops in my career. I also visit pet stores around the country when I travel and know this to be true as well. I hear a lot of bad info coming from salespeople.
So where are you to get the best advice? I don't know what part of Maine you are in ( I am in the Northeast area of Maine every summer
) but if there is a local fish group in your area, join it. Those people will likely be dealing with the same water you are working with, the same fish sources you are dealing with and the leaders of the group will be the "seasoned" fish keepers. If there are no local groups to you, there is always here on AA
. Then there is always the internet itself but just be forwarned, the information you get from fish sites online are talking about wild caught fish so unless you are getting wild caught fish, the information you are reading online may not apply to your fish. Many fish species in the hobby today are either farmed or do not exist in the wild and are no longer bred in the water parameters their wild ancestors needed to breed. Your Angelfish is a perfect example of this. I produced over 1million Angelfish for the trade in one of my hatcheries in water that had pH 8.2-8.4 and hardness ( GH) was over 350 ppm ( 20 degrees hardness). Do an internet search and see what it says to breed wild angelfish.
So as a new fish keeper, you need to be careful with where you get your info from. What worked for someone in say Nebraska, may not work in Maine. What worked for someone in a species only tank may not be the same experience in a community tank. People's experiences with a single fish may not always be the norm but an exception. Water parameters are especially important when it comes to medicating fish as well. Not all meds work in all water parameters.
So now that you are overwhelmed with all this new information
, you are now a better informed hobbyist.
Resist the urge to impulse buy. Research, research, research before making any purchases as to whether it's a good fit for your tank. Fish keeping can be a very interesting and enjoyable hobby if you do it right but it can be very frustrating if you do it wrong.
I've only been keeping fish for 60 years now so you know it can be done.
