What temp do you keep your tanks at? Aren't horns coldwater sharks and bamboo and epaulette warm watered?
NO - Horn Sharks (Heterodontus francisci) aren't cold water sharks - they are temperature water sharks - which is to say they can withstand water temperatures between 60-80F. Most Studies show that Horns actually prefer water temps above 68F. So the 75F that Rich has his tanks at is nearly perfect for both the eppie, & bamboo as well as the Horns.
Also the larger Horn and eppie should reach maturity in about 1 year or less, at which point the growth rates of each should slow down. The smaller Horn & Bamboo each still have a couple of years to go before they reach maturity.