how the fish was injured

Euthanizing a sick, dying or injured fish

For better or worse, an experience with my personal saltwater aquarium inspired this week’s post. An incident in my tank this week has me asking the question:

When, if ever, is it O.K. to euthanize a sick, dying or injured fish or coral?

Unfortunately, I found myself tired (from a long day at work) wondering what the answer was to this very question. Perhaps I was traumatized at a fragile age by watching the classic movie Old Yeller, but this wasn’t an easy topic for me to contemplate. If my pet of choice here was a dog or a cat, I would have the advantage of a medical expert there to provide their medical opinion about whether or not it was time to put my pet to sleep. But in this hobby (which is expensive enough already without veterinary bills), we are on our own. But the ultimate decision wasn’t the only thing I was alone on this week.

The scene was a bit morbid. I thought about taking a picture of what had happened, but I chose not to, for a variety of reasons. In a nutshell, one of my engineer gobies, sadly, got stuck in and mangled by one of the powerheads. I didn’t see it happen. I have no idea how long he was stuck there, but around 8pm (later than usual) when I sat in front of my tank, ready to feed my little guys, I caught the strange swaying motion out of the corner of my eye.

when is it ok to euthanize a fish
image from Wikipedia

The powerhead sat high in my tank, pointed at a downward angle, sweeping more than 1200 gallons of water across the top of the live rock in my tank hour after hour. Most of the action seemed to happen at levels of the tank below the powerhead. What caught my eye was the gentle swaying of the slender body of the fish.

Upon closer examination, I found that the goby had somehow swam upstream, into the 1200 GPH flow, where the powerhead was essentially open except for a small grid shaped like a + sign, dissecting the opening like a mathematical grid into quadrants. The fish (often confused for an eel by the unititiated) then somehow made an abrupt left-turn with its snake-like body ahead of the impeller, but instead of going out the same way it came in, the fish must have attempted to flee by trying to cram itself through one of the side vents in the powerhead.

The physics of this last part amazes me. Somehow, the poor, undoubtedly panicked fish (probably 7 inches long) shoved his 1/2-inch tall head through an 1/8-inch wide slit in the side of the powerhead. He managed to get about 3 of 7 inches through before getting stuck. The bottom half of his body was bent at a right angle in the flow of the current.

how the fish was injured

I did the only thing I could think of. I unplugged the powerhead, detached it from the wall of the tank and hoped he would swim free. He didn’t. His breathing was labored but he was fighting to keep his head up (literally), so I moved him to a specimen container (gently) keeping him underwater the entire time, so I could get a better look.

With two levers, I leaned on the plastic, opening it up more…enough that he should have been able to swim out (if he could swim), but the fish didn’t budge. After a few more minutes, that felt like hours, assessing the scene, I figured out a way to stretch the opening with a single hand (rotating the lever like screwdriver) allowing me to gently pull the fish out with my free hand.

With the extra leverage holding the opening wider, the slime-coated fish slipped out with depressingly little pressure. In some respect, I’m relieved the extraction was simple, but in another sense, it seems like such a shame that the fish was so close to getting free on its own power. A fraction of an inch in any direction would have made the scene entirely different.

The fish was seriously injured. A huge section of skin and muscle was worn away (apparently by the powerful impeller). The fish couldn’t swim, and his breathing was slow and labored. After using the jaws of life to remove him from the vice. I sat there for a brief moment watching him suffer, convinced the injuries were terminal, wondering whether it would be better to let him expire on his own or softly put him to sleep.

What would you have done? More importantly, what should I do to be prepared for this moment (if anything) moving forward?






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