The marine animal tunicate can be used both as biofuel and fish food, according to new research. On the ocean floor, under the pier, and on ship ropes – that’s where the tunicates live. Tunicates are marine filter feeders that serve as bacteria eaters and as a foodstuff in Korea and Japan. But in the future they may become more prevalent. Researchers have found that a certain type of tunicate – ascidiacea – can be used as a renewable source of biofuel and fish food.