I would rehome that shark asap. I had one in my planted tank about 2 years ago. He was great for the first 9 months or so, then went nuts ant started killing everything. Keep that water clean so the other fish can recover. What is the current tank temp? You may want to turn it up a little as well.
46 Bow Front Planted
Eheim 2217 & 2236, 2-39wt T5 bulbs (10,000), 72-75*
Pristella tetras, cardinal tetra, amano shirmp, bamboo shrimp, nerite snails, assassin snails and red cherry shrimp.