These are the little springy steel clips used to secure the clear acrylic lighting cover in place on the Aqua One 620 and 620T. The clips are frequently subject to corrosion but thankfully easily replaced. Just pop the old ones off and replace with new ones.
Great Value Twinpack of Aqua One high output replacement Sunlight / Tropical mix fluorescent lighting tube. This Multipack contains 2 x PL-18w Sunlight / Tropical tubes.