interesting thought. I cant really think of why the has to be a minimum or maximum hight so I guess ur thoughts about their native habitat would be correct. That said they are found down to depths of over 2m so i guess you could work the arguement both ways.
I guess it comes down to volume. I would see no issues breeding in a tank that was say 20cms high as long as the volume of water in the tank was over 60ltrs (about the minimum i recommend to breed in).
the other thing to consider is that you need space to get in above the tank and use nets etc. Something I failed to take into consideration when i first set up my fish room

Lucky for me my racks are simple to remodel. if you were custom making a set or racks then you would be stuck

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