Sorry about your fish.
That kind of thing can happen when keeping fish with high territorial/sexual aggressiveness.
Having a plan to deal with situations, just like yours, is a big plus.
We all need a basic set of materials, some you might already have, but have not looked at as aquarium supplies.
A waterproof, non toxic container to act as a “hospital tank” is a must have item.
5-10 gallon will work for most situations. This size sterlite/Rubbermaid is very cheap. It`s size is such that it can be stored most anywhere. Most will come with a lid, to keep it clean and ready for instant use.
This container can hold all your “emergency ward” tools when not in use.
Aquarium salt, non iodized table salt can be used.
An air pump, with some tubing and diffusing system. I prefer the small, in tank filters, which are often sold as a package, with air pump, filter housing, and an initial media pack.
A small heater would round out your “ambu-tank”.
Other medications can be on hand as well, though I tend not to use any more chemicals than absolutely necessary, as they have the potential to cause as much damage as the injury you are trying to treat.
With these few, inexpensive tools on hand. You can deal with 99% of your tank emergency/rescue situations
Good luck with your fish..
All Malawi,All Mbuna,All Action,All the Time