Marine fish are sold in two different ways.
Some species (blennies, gobies, dartfish [firefish], fairy wrasses, royal gramma, some small damsels, dwarf angels, dragonets, dwarf lions and some eels) are sold as adults, caught in the wild.
Notably perc clowns, clarkii clowns and cardinal fish are bred in captivity and are sold small, but don't grow too huge. Pretty close to 'what you see is what you get.'
There is a small middle range, which includes the 5-inchers: the larger clowns, larger damsels (except the garabaldi). Some blennies and gobies almost get this big, but being long and skinny, don't mass near as much, and they're quiet foragers. Not-reef-safe wrasses come in at the top of this size range, and a shade larger.
Then there are the others, which are caught in the wild as juveniles, nearly minnows compared to what they become, and these are the 10-12 inchers that tend to be shaped like a dinner plate, which are the full-sized angels, tangs, rabbitfish, the garabaldi damsel, some wrasses, and such. These grow pretty fast. Angels and the garabaldi and some wrasses drastically change colors and often don't look a thing like the juvie form. Large tangs can be longer than 12 inches, and are massively muscled. Having to extract one of these fish from a tank is quite an operation. These big guys also swim fast, and swim long: they require running room to be healthy.
And of course the ocean is full of really, really big fish that we can't keep.
There is absolutely no truth to the myth that fish grow to fit their tank: if a fish is in a too-small tank, some juvies panic and pace, even though they have room enough for their size. They don't exercise enough, often have physical problems, and aren't healthy. Rabbits which are timid and non-aggressive will start doing in their tankmates, because they feel cornered, and freak.
Fish grow very fast when healthy and well fed. Buying a fish in the hope of a larger tank is not a good idea: you'll be forced to it in about a year, which means re-buying all your equipment, from skimmer to pump to, well, you get the idea. Delay getting your rig until you can afford the tank that will support the fish you want. Why do stores sell 30 gallon tanks---and tangs and angels that require 300 gallons---to the same customer? Because larger tanks come in many shapes, are very spendy, often custom built, and somewhat specialized. But the stores need to sell some sort of glass box to put your fish in. So they offer you little tanks, but also sell big fish, and unfortunately, don't tell you that A doesn't fit B. This is why good marine fish stores are rare. I might add, these little tanks can be pretty good with some corals, but unfortunately many hobbyists are scared of corals---which will grow like mad and never carpet-surf, if you can just get your water right in the first place [which is not rocket science.]
Ask around Reef Central, talk to senior members, talk to the mods, ask questions. We'll be happy to advise you. Find out what you need, both size and brands, and then you might be safe looking online for a good system, because good ones can be had out there.
Some species (blennies, gobies, dartfish [firefish], fairy wrasses, royal gramma, some small damsels, dwarf angels, dragonets, dwarf lions and some eels) are sold as adults, caught in the wild.
Notably perc clowns, clarkii clowns and cardinal fish are bred in captivity and are sold small, but don't grow too huge. Pretty close to 'what you see is what you get.'
There is a small middle range, which includes the 5-inchers: the larger clowns, larger damsels (except the garabaldi). Some blennies and gobies almost get this big, but being long and skinny, don't mass near as much, and they're quiet foragers. Not-reef-safe wrasses come in at the top of this size range, and a shade larger.
Then there are the others, which are caught in the wild as juveniles, nearly minnows compared to what they become, and these are the 10-12 inchers that tend to be shaped like a dinner plate, which are the full-sized angels, tangs, rabbitfish, the garabaldi damsel, some wrasses, and such. These grow pretty fast. Angels and the garabaldi and some wrasses drastically change colors and often don't look a thing like the juvie form. Large tangs can be longer than 12 inches, and are massively muscled. Having to extract one of these fish from a tank is quite an operation. These big guys also swim fast, and swim long: they require running room to be healthy.
And of course the ocean is full of really, really big fish that we can't keep.
There is absolutely no truth to the myth that fish grow to fit their tank: if a fish is in a too-small tank, some juvies panic and pace, even though they have room enough for their size. They don't exercise enough, often have physical problems, and aren't healthy. Rabbits which are timid and non-aggressive will start doing in their tankmates, because they feel cornered, and freak.
Fish grow very fast when healthy and well fed. Buying a fish in the hope of a larger tank is not a good idea: you'll be forced to it in about a year, which means re-buying all your equipment, from skimmer to pump to, well, you get the idea. Delay getting your rig until you can afford the tank that will support the fish you want. Why do stores sell 30 gallon tanks---and tangs and angels that require 300 gallons---to the same customer? Because larger tanks come in many shapes, are very spendy, often custom built, and somewhat specialized. But the stores need to sell some sort of glass box to put your fish in. So they offer you little tanks, but also sell big fish, and unfortunately, don't tell you that A doesn't fit B. This is why good marine fish stores are rare. I might add, these little tanks can be pretty good with some corals, but unfortunately many hobbyists are scared of corals---which will grow like mad and never carpet-surf, if you can just get your water right in the first place [which is not rocket science.]
Ask around Reef Central, talk to senior members, talk to the mods, ask questions. We'll be happy to advise you. Find out what you need, both size and brands, and then you might be safe looking online for a good system, because good ones can be had out there.
