Need help... Stingray predator tank

I have a california round stingray i belive. He is in a 125 gallon tank with 1 lionfish 1 niger triger and 1 clown grouper. Im pretty sure im overstocked just with the stingray. I really love this guy and dont wann get rid of him . but i will if he needs a bigger tank. Depending on what size i could buy it because my fish room is jam packed with about 10 aquariums. I have a huge filter so filtration isnt a problem.... Any help ease Nd thNks.