It's not often a shark finds itself on the menu, but this whitetip reef shark was knocked a rung or two down the food chain when a hungry (and bigger) beast decided to take a bite out of it. The deep-sea predator launched the vicious attack on its smaller tank-mate at the Aqua World aquarium in Oarai, Japan.But after a 40-minute battle to try and swallow the fish, the nine-foot sand tiger spat out his smaller cousin because it found it too chewy.Staff at the aquarium said they were shocked when their star-attraction tried to eat the smaller whitetip reef shark, with the animals usually so well fed that they ignore their tank mates entirely.But the sand tiger had not been eating in recent weeks, with staff concerned over its apparent lack of appetite.But that changed when it decided to make a smaller tank-mate breakfast.A caretaker doing his early morning rounds saw that the nine-foot long shark had began biting the whitetip and immediately called keepers for help.After trying several times to bite a chunk out of its smaller relative and failing because if its thick skin, the shark gave up and tried to swallow the smaller shark whole.The bemused caretaker witnessed a titanic 40 minute struggle between the two predators of the deep before the tiger shark gave up the fight and spat out his prey in disgust.Staff managed to rescue the injured whitetip and pull it to safety, but it was so badly mauled it later died from its wounds.'In light of this event, we will be further increasing the effort we make when judging which sharks to place in the same tanks, taking into account their relative size and possible hostilities,' a spokesperson for the aquarium said.In the meantime, Aqua World hopes visitors 'will continue to support the facility and its Sea of Sharks exhibit.'(dailymail.co.uk)BakuDaily.Az