You could take 4 2x2s and rest a 1/2" plywood top on it with no connectors at all and it would take the weight in your picture. Regardless, it is still not proper aquarium stand construction. Will it ever fail? Probably not with that sized tank. Poseidon's tank is proper construction for a tank with wood supporting the tank to the floor. If you are going to do something, do it right. If that means redoing something, so be it.
Just rude man, offer input but to tell him he is wrong isn't right.

