Baracudas in the blue is a tricky fish to shoot as they are rather reflective and the nearest ones burn out.
1° You should position yourself that you have them alineatet all on the same distance
2° reduce the strobe power to expose the nearest ones right or a little underexposed to avoid burn out the light parts
3° you should use mainly ambient light and use the strobe just to lighten them enough to isolate them from the background
4° having the sun in your back will help greatly to iluminate them by the sun and you may shoot only in ambient light
5° shooting them against the sun creat spectacular photos, but you need to consider hints 1-3 and master your strobe output
6° if they are stationary and not shy you may switch to spot metering to get the nearest/lightest one exposed right while the farer ones get graduately underexposed
You rather underexpose a bit and later adjust brightness, shadows and highlits on the computer than burning the whites.