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), 75-78*
Amazon sword, red lotus, Christmas moss, and crypt lutea, Wisteria, Crypt Wendtii, Water Sprite.
12 pristella tetras, 23 cardinal tetra, 8 amano shirmp, 2 bamboo/flower shrimp, 1 mystery snail, 2 nerite snails, several assassin snails and cherry shrimp.