Goby species interact and maintain long-term associations with sponges. Sponge-dwelling gobies benefit from protection within sponge tubes by using them as microhabitats. Although sponges are hypothesized to benefit from gobies consuming polychaete parasites or clearing sediment from filtering tissue, which improves their pumping rates, increases in pumping efficiency have not yet been demonstrated. Here, we investigated goby associations with two sponge species with similar tube morphologies (Aplysina lacunosa [convoluted barrel sponge] and A. archeri [stove pipe sponge]) in Bonaire, Dutch Caribbean. We visually assessed yellowline goby, Elacatinus horsti, presence in sponges. Then, we used in situ methods with fluorescein dye to estimate pumping rates by analyzing videos of dye front movement in tubes attached to sponges. There was a higher frequency of gobies in A. archeri (46%) than in A. lacunosa (26%) sponges. For A. archeri, pump rates were higher for longer sponges but size did not affect pump rates of A. lacunosa. For both sponge species, pump rates of tubes with gobies were significantly higher than those of tubes without gobies (p<0.05). Therefore, these goby-sponge associations, and perhaps others, are likely mutualistic relationships in which sponge hosts benefit from higher feeding rates when gobies are present.