Goldfish exposed to UV light for prolonged periods may experience damage to their skin and eyes, which can lead to health problems. However, goldfish exposed to UV light for short periods, such as during water changes or tank cleaning, are unlikely to experience any adverse effects.
Is it necessary to use a UV sterilizer in a goldfish aquarium? No, its not strictly necessary, but it can be a valuable tool for maintaining water quality and preventing disease outbreaks, particularly in larger tanks or those with a higher bioload.
Pros and cons of UV sterilizers for fish tanks: effects on fish health, algae, water clarity, maintenance, cost, and usage tips.

Goldfish Pond UV Sterilizers, sometimes called UV clarifiers are the simple answer to green water in your Goldfish or Koi pond.
Yes, a UV sterilizer is generally safe for goldfish when used correctly. In fact, it can offer several benefits to their health and environment.

As we can see from the illustration, Effects Of Uv Sterilizers On Goldfish Health has many fascinating aspects to explore.
Category A, B, & C Sterilizers. Affect on green water, disease prevention, & Redox.An example of design having an effect on exposure/dwell time is having water deflection shields where the water enters and exists the UV Sterilizer at the connections/hose barbs (such as in TMC UVs).