Well, hate to say it but you should've planned and researched first.
You could probably make a small tank for them, and have the top covered with custom cut thick acrylic. Or fine meshed screen.
But Bro, if you ever have kids or uninformed relatives, I would strongly suggest taking them down humanely instead of keeping them. Masyadong risky kasi. Putting them down humanely would probably be more responsible and safe. You may never know, they may become a very dangerous pest should they ever be released on the wrong waters. Parang yung mga lionfish lang na naging peste sa ibang bansa. Mahirap din kung magreproduce yan na walang natural predator tapos dumami baka di na tayo makapag swimming haha