With the sailfin, anglefish and hatchet in the big tank - I would look to add some colorful fish that are bottom dwellers (since the others are not).
In that regard, I would suggest either getting some small clown loaches and/or some dwarf cichlids (probably Apistogrammas if you want the color). Apistogramma Cacutoide Triple red are very stunning / colorful fish. There are also several other Apistos that show lots of color.
If you want to add a few more fish to your mid level, I like the suggestion of some colorful tetras. Rummynose are my favorite - but Lemon Tetras kept on a school in a well kept tank also can be quite stunning.
In that regard, I would suggest either getting some small clown loaches and/or some dwarf cichlids (probably Apistogrammas if you want the color). Apistogramma Cacutoide Triple red are very stunning / colorful fish. There are also several other Apistos that show lots of color.
If you want to add a few more fish to your mid level, I like the suggestion of some colorful tetras. Rummynose are my favorite - but Lemon Tetras kept on a school in a well kept tank also can be quite stunning.
