Mudkipper trying to catch flies on the nose of a 5m long Saltwater Crocodile. In this case it’s doing the crocodile a favour. March Flies attack the soft flesh around the eyes and nose of crocodiles, and the mudskippers hop onto the crocodile to ambush the flies.. this could be classed as type of symbiotic relationship called ‘mutualism’ Mudskippers are carnivorous amphibious fish, and there are 23 extant species of Mudskipper on earth. They’re quite a remarkable species, and some can grow to 30