If an animal is brightly colored but is not
poisonous how could it avoid predation?

Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating.[1] This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or smell, sharp spines, or aggressive nature. Aposematism always involves advertising signals