I believe my very good friend Gork, on X, has wise answers and suggestions:
"Placing M6 stainless steel nuts around the tubing of an air diffuser at the bottom of a pond introduces some risks concerning interaction with koi fish. While stainless steel is generally durable and less prone to rust, the size and shape of M6 nuts (which are about 6mm in diameter) could potentially be a hazard to koi, especially the larger ones:
- Ingestibility: Koi are known to be curious and sometimes ingest small objects they encounter in the pond. The size of M6 nuts is small enough that a large koi might attempt to eat or at least mouth these nuts. If a koi manages to swallow a nut, it could lead to serious health issues like blockages in their digestive tract.
- Weight and Placement: While the nuts are intended to keep the air diffuser stone in place, they might not be heavy enough to prevent the stone from floating or shifting if there's significant water movement or if the koi disturb them. This could lead to the nuts becoming loose or accessible to the fish.
- Safety Considerations: Even if the nuts do not get ingested, they could potentially injure a koi if the fish bites or plays with them. The sharp edges of nuts could cause mouth injuries or external damage if a fish accidentally gets pinned or scraped by them.
Given these considerations, here are some safer alternatives to using M6 nuts:
- Use Weighted Tubing: There are air lines specifically designed to sink, which might eliminate the need for extra weights entirely. These can be found in pond supply stores or online.
- Heavier or Different Weights: If weights are necessary, consider using materials that are less likely to be eaten or cause harm, like larger, smoother stones or specially designed pond weights that are too big for koi to swallow.
- Airstone Design: Some air diffusers come with built-in weights or are designed to be heavy enough to stay at the bottom without additional weights, reducing the risk to fish.
In summary, while it's not highly probable that a koi would eat M6 stainless nuts, the risk is present, especially with larger or more curious fish. It's advisable to avoid using such small, potentially ingestible objects in an environment with koi to prevent any health risks to the fish. Instead, opt for safer, pond-specific solutions for anchoring air diffusers."
- Gork
Anyone knows where to get low-cost heavy air tubing or heavy air stones?
I will try to find a big smooth rock with the right shape.
