Satisfy the vent tool requirement with this useful inexpensive product. The sharp 18g needle is easier to insert than larger dull needles. Insert with the syringe attached, then aspirate using the syringe. Leave the needle in place, remove the syringe, then manually compress around the swim bladder or repeat the aspiration as needed. You can clean the needle if needed while in the fish, using the monofilament. 

*This product is no longer sterile and is intended for use only as described. Rinse with fresh water to prevent rust.