opinions is this ca or just the lighting

[jann1033]

took this inside with my 50mmf1.8 lens at 1.8., never used that lens this open before since it didn't af on my old body. all the photos i took at this one tank have the blue on them but the lighting was blue, so i can't tell if the tentacles are blue from the lighting or ca or fringing. I've tried to adjust the ca and fringing in lightroom but it really only makes a minor difference so before i go completely insane trying to adjust something nonadjustable what does it look like it is to you

thanks