I thought I would cover a topic that most wild betta keepers would be familiar with. I'm sure there are more than a few of us out there, who have lost fish to jumping. I think a lot of people don't realise just how small a gap some of these wild bettas can squeeze themselves through, until it happens to them.
As I have stated countless times, I keep predominately coccina complex species. However, in the past I did dabble with members of the unimaculata complex and I do currently own a group of B. unimaculata.
Based on my experiences, I found this complex is the absolute worst at getting out of their tanks.
I have lost an ideii male and more than a handful of unimaculata to jumping. This was even with a cling wrap cover over the tops of the tanks.
They are just such big, strong fish that they can push through the cling wrap if it is not 100% stuck down. Therefore, nowadays I use cling wrap with a heavy glass cover on top, to make sure that no one is going to get through.
I have also lost quite a few of my coccina complex species through jumping. Mostly this was either newly purchased fish who were still settling in and quick to startle, or juveniles who for some reason or another decided to commit mass suicide the one time I left their tank uncovered.
It is a horrible way to lose a fish, as it is almost 100% preventable. I still can't believe how fortunate I was that none of my coccina or rutilans jumped out when I first had them and their tanks were left uncovered.
While some people use plants at the surface, or drop the water level down to discourage jumping, there is still always the risk that one day the fish will spook and go up and out.
For me personally, it is just not worth the risk. While it is time-consuming to have to put new cling wrap on every water change, the benefits far outweigh any annoyance and I have not had a single fatality among my clarets since I started using it on their tanks.
Hailing from Melbourne, Australia, I currently keep and breed a number of species from the coccina complex.