Orange roughy fish are a fourth-level consumer. we may see fifth- or sixth-level consumers, but not as many as at lower levels on a trophic pyramid. why are the upper levels of a tropic pyramid limited?

An ecological pyramid is a graphical representation of the distribution of the biomass to different organisms in successive trophic levels. The energy is being lost by 10% in every higher trophic level, when one organism is consumed by another organism in a food chain. Therefore, the number of trophic levels in a pyramid will be limited.  

answer: accepted answer: aquatic animals use the oxygen dissolved in water to carry out respiration. since the amount of dissolved oxygen in water is low as compared to the amount of oxygen in the air, therefore the rate of breathing in aquatic animals is much faster than it is in terrestrial animals.

explanation: