The senegal bichir is often sold as a dinosaur eel, they can grow at least 12" long and will eat anything that can fit in their mouths. They need to be kept with large non agressive fish. Do a google search to find out more. If you want something eel like to fit in with your current fish take a look at khuli loaches they are great little fish which only groww 4 inch long.
Hope this helps
Emma
looking back at your current fish i see you already have the loach i would get him some friends and forget the eel