I have never kept plants before. But someone I bought a tank from gave me these. They look pretty sickly. What do I do to keep them alive and make them healthy again? I can't really change my lights, but is there anything I can do to help them until I get better lights? They're in 30 gallons with ghost shrimp, fancy guppies, Cory cats, zebra and long finned danios, a pearl gourami, mystery snails. Everything stays well fed, will they eat them?