Which Fish Turned Out Differently Than You Expected?

Daniel@R2R · 2026-09-29T10:04:26-0400

Some fish settle into a reef exactly as predicted. Others grow, mature, and reveal an entirely different personality.

A peaceful fish becomes territorial. A shy fish becomes the tank’s unofficial host. A drab juvenile develops unexpected colors—or a fish you thought would stay small becomes the reason you need a larger tank.

Which fish has surprised you the most as it grew or settled into your reef?

BONUS POINTS: Tell us what you expected, what actually happened, and whether the change made you like the fish more—or made you rethink keeping it.

littlefoxx · 2026-09-29T10:53:05-0400

I used to have a sohal and he was always out and about and seemed to bond with me. Always came up to the glass when I went up to the tank and would sit eye level with me

Euphylliaphyle · 2026-09-29T18:49:51-0400

Voted Other: How could you leave out sex? That seems pretty significant to me!

Daniel@R2R · 2026-09-29T19:44:39-0400

Euphylliaphyle said:
Voted Other: How could you leave out sex? That seems pretty significant to me!

Fair enough! Haha

mcarroll · 2026-09-29T20:18:49-0400

Six lined wrasse. I had a 36" tank that was just growing SPS corals for a couple of years and doing great at it. My buddy would come over and watch the copepods, mysids and amphipods swimming around mid-water and everywhere else like they owned the tank. I finally decided to try a fish (I was really just into corals) so I brought home a small 1" six-line. He went nuts on all the pods and then two days later jumped out for no apparent reason, even though he was the only fish! My only guess was the serpent start I had went hunting and spooked him while sleeping or something. I went back to enjoying corals more.....they *never* jump out.

13rodo · 2026-09-29T21:02:04-0400

My chalk basslet has just surprised me in every way.

It’s friendly. It always interacts with me when I’m in the room. When I moved everyone to my 75g from the 15g, it slept and stayed within a few inches of his buddy (my Yasha Goby) for the first week.

It’s strikingly colorful. I don’t really know how to explain it… it’s just much more beautiful in person than any picture.

Dunno… I have some really cool fish now, some that I wanted from the start. My favorite is the one that I bought on a whim

Maho.B · 2026-09-29T21:24:26-0400

In my very first reef tank (40 breeder) I added a neon dottyback. Back then (1990) there wasn't much info on them or at least that my LFS had. It was an absolute model citizen with all my other peaceful fish. Fast forward to today and they are always classified as aggressive. Maybe I got lucky with that one, but anyway, it was easily the most interesting fish in terms of nature reef type behavior. Such a cool little fish that blew away my expectations!