Hi
I have a D7000 in an ikelite housing, so happy to share my thoughts and experience.
Ikelite strobes are quality and make sense when going with an ikelite housing as TTL functionality is built in. The 161s are great. I have one paired with an older 125 (purely for financial reasons).
As far as lenses go, the accepted "go to" lenses are the tokina 10-17 fisheye for wide angle, and either a nikkor 60 mm 2.8 macro (d or g version), or 105 mm. I have the 60 mm, which I find great. You need to get a little closer for macro shots, but I think provides an easier working distance to also shoot fish portraits.
With those lenses you can't go wrong. You'll need to get a flat port for the macro lens and a dome for the fisheye. You can either go with the large ikelite dome, or a smaller dome that will allow you to get closer to things for "close focus wide angle" (CFWA) shots.
I've recently invested in a vivid housing leak sentinel for my set up. Also really worth looking into to give you peace of mind with all that expensive gear!
Hope that helps. Happy to answer any further questions.
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