Thank you for using our service to ask your question. I am a veterinarian and will do my best to help.
I would need a little more information to answer your question well. For instance, what body part is being tapped to remove fluid? It is more risky to remove fluid from the chest as opposed to the abdomen, and even less risk to tap fluid that is just under the skin.
I would assess a dog's heart, pulses, and blood counts usually before doing a tap of any kind. If I could use ultrasound the area to be tapped first, and use ultrasound to guide the needle, that decreases risk. However, in an emergency, I have jumped right in and tapped a chest of a dog that might die if I don't act. Knowing what condition he had, what kind of fluid (blood, pus, serum) is being removed, and what health issues the dog has would affect my decision about tapping.
Could you tell me a little more about why Benji needed a tap, what area of his body was tapped, and what was found and what happened?