Just so everyone knows this is what the fish tank is. Not sure but I think it increases one of the stats of all fish weapons: laser fish, fish, heavenly sword e.c.t :
One Shotting Bosses with the laser fish (not a bug, just a feature) : r/ SoulKnight
Here's a terribly made and argument causing laser weapon tier list : r/ SoulKnight
So my pet tuna can use master spark (screenshot from soul knight the weapon I'm using is called laser fish) | Touhou Project Amino
Laser | Soul Knight Wiki | Fandom
Triple Deep-sea Laser Fish 🎏 | Fandom
Grilled Laser Fish | Soul Knight Wiki | Fandom
OP GLITCH/BUG* Laser Fish Unlimited Damage! - Soul Knight 2.5.5 - YouTube
Soul knight - whats the difference between ion laser and laser fish - YouTube
Laser Fish | Soul Knight Wiki | Fandom
Handmade Rod | Soul Knight Wiki | Fandom
Laser Therapy | Soul Knight Wiki | Fandom
Fish+gun=win : r/SoulKnight
Making a Laser Fish From Soul Knight IRL - YouTube
Baby Laser Fish | Soul Knight Wiki | Fandom
ALL 8 NEW Weapons Can Be Fished In Soul Knight - YouTube