Range Minimu Query: Given an array A[1,n] of n ordered objects (such as numbers), a Range Minimum Query (or RMQ) from i to j asks for the position of a minimum element in the sub-array A[i,j]. RMQs can be used to solve the lowest common ancestor problem.
The reasons that we do not eat or recommend shellfish are very similar. Shellfish are bottom feeders and feed on parasites and dead skin, many times from dead animals. They do not have appropriate digestive and filter systems to purify toxins and parasites from their body and flesh.
Angelfish should not be kept with discus. Angelfish is another fish that should not be kept with discus. They are too aggressive, especially when they reach sexual maturity and will try to take over the entire tank forcing the discus to hide.