Good afternoon, Has anyone had experience keeping these 2 fish together? I introduced them and seem to be getting along so far with the Undulated being more shy and grouper swimming around freely
I cannot answer your pairing directly, but I have a somewhat relevant experience.
I got my current 75-gallon FOWLR from a co-worker a little over a year ago. It already contained three triggerfish: an undulate (
Balistapus undulatus), a Picasso (
Rhinecanthus aculeatus) and a rectangle (
Rhinecanthus rectangulus). All were around 3-3.5" long.
At first, the Picasso was the largest and most bold/dominant, the rectangle was smaller and mostly peaceful while being chased occasionally by the Picasso with no major aggression and no damage, and the undulate was smallest and hid most of the time.
Within the first few months, I noticed the undulate growing faster than the other two and becoming a bit more bold over time. I knew this may eventually become an issue with 3 triggers, especially since the undulates are known for aggression.
About a month ago, I noticed the Picasso hiding and the undulate out a lot more. Within 2 days, before I separated them, the undulate killed the Picasso due to aggression and scared the rectangle into hiding. There were a few bite marks on the Picasso and it had tattered fins. At this point, I had a quarantine tank setup and cycling with a piece of live rock, but I could not catch the undulate that night.
The next night, when I got home from work, I found the rectangle dead as well from aggression. I immediately did anything necessary to remove the undulate before it killed any more of my fish (purple tang, chromis, and snowflake eel). I rehomed the undulate to another co-worker's tank and it has been doing fine since.
I am now (and was before, though I acquired the tank with those occupants) a firm believer that undulate triggerfish are a great risk in a tank with other occupants and there is valid reason for the warnings I have read about their disposition in my saltwater reference books and online.
Maybe they can be peaceful, but they seem to be a high risk.