An ecological size spectrum is the distribution of body sizes in an ecological community. Projecting future population growth requires knowledge of size spectra because vital rates such as growth and survival are often size dependent. Changes to ecological size spectra might also be used as ecological indicators of e.g. primary productivity, or recovery from anthropogenic disturbances. Power law distributions such as the bounded power law are often used as models for size spectra. However, using coral and fish data from the East Australian biogeographic transition zone, we show that bounded power law might not be the best fit for ecological data, especially at the tail of the distribution (larger sizes). We also consider the problem of size-biased sampling of coral colonies from benthic photo transects, which occurs because larger colonies are less likely than smaller colonies to fit entirely in the field of view. Our results suggest that ecologists should consider the choice of distribution used in their size spectra modelling more carefully.