The Fish Products You ACTUALLY Need

a hand is pouring water onto a pool.

There have been countless appointments where our veterinary staff gets a long history of illness accompanied by 10-20 different OTC fish tank products. Some claiming this, others that; none of which help treat the problem. Of all the “magical” over-the-counter fish products and pond additives, which ones do you ACTUALLY need?

Water Conditioner/Dechlorinator

This product makes tap water safe for fish. Make sure you use one that treats chlorine AND chloramine. Ammonia binders are not necessary if your filter is working. And those that promote slime coats, don’t really do that. Use it every time you add city water to your system.

Barley for Algae Control

This is a preemptive treatment, so don’t expect it to work on any of the algae you already have. In combination with a UV light, this will help keep your algae levels down. It is a very safe product for fish. If you still have algae problems, make sure your nitrates are under control.

And that’s it.

What fish products you DON’T need:

Beneficial bacteria

Most of these products are barely alive by the time you purchase them. Back in the day, it was thought that mainly Nitrosomas and Nitrobacter spp. of bacteria were responsible for your nitrogen cycle. Newer research has come to find thousands of potential bacteria that take part in your nitrogen cycle, and most systems have their own unique signature. What works in your pond will not be the same in your indoor tank or your neighbor’s system.

And when starting a system from scratch, your fish will bring their own bacteria. Yes, it will take time, which is why you should start with a low bioload to keep your system from crashing. Those bacteria that you’re adding, again, if they are alive, will work for a few days and maybe some will stay and populate your filters. Our office testing 5 different products when we were getting our systems up and running. You know how many made a signficant difference? ZERO.

Sure, these products won’t hurt your fish, so if you don’t believe me, you can still add them. But you might as well save the money for more water changes!

Tea-tree oil fish products

These have been proven to not change a single thing about your fishes’ “infections.” They create lots of bubbles and smell good, but aren’t effective therapy… for anything.

Liquid algecide

Fish + water = algae. There’s really no way around it. Algae doesn’t bother fish, provided there is enough oxygen to go around; algae bothers people. However, some fish are not keen on many of these products. You may seen lethargic or decreased appetite when you use these with naive fish. Before you add them to your pond, make sure you know your total volume! We recommend a barley + UV light + rake (i.e. manual labor) approach, which is 100% safe for fish.

Particulate coagulants

The liquid-based products that help settle out small particles, do so by making them stick together and become bigger, heavier particles. These have also been shown to cause respiratory distress in fish. The exact reasoning is not known at this time, but there are other, safer ways to remove small particulates in your pond or tank, such as floss or fine mesh. As with the liquid algecide, be sure you know the exact volume of your pond for proper dosing.

“Enzyme” clarifiers

Some of our clients love these products, but you really don’t need to use them. If there is a lot of waste in your pond/tank, vacuum it out! Or have a pond professional retrofit a bottom drain to help suck the waste out to your filters. No fish really like swimming in their own waste.


Many owners will add salt to their ponds and tanks constantly at very low levels. Why? Well, it can help with parasite loads, algae and osmoregulation, but levels will need to be higher than 0.15%. And measuring by teaspoons is ridiculous. Sorry folks, but you need to weigh your salt for accurate dosing. If you are using an electronic probe, be sure to calibrate it every 3-6 months.

Continuous low levels of salt has been shown to create more salt-resistant parasites, requiring higher doses for effective treatment. If you don’t know why you’re adding salt, you can stop.

Antibiotics/Antiparasitics/”General cure”

If your fish is actually sick, what your veterinarian prescribes has actually been checked by the FDA and is effective therapy. Over-the-counter products are not checked by the FDA. Most antibiotics will also wipe out your biological filtration. Giving medications through injection or medicated feed is more effective, but you will need your veterinarian.

Using non-prescribed medications put your fish at risk for developing resistant bacterial infections. If these get in your system, it’s very hard to treat. Only treat with antibiotic medications when directed by a veterinarian.

Antiparasitic treatments are less regulated, but not all treatments are effective against all parasites. Your veterinarian will diagnose the parasite present and prescribe a treatment tailor-made for your pond. Our office uses USDA-approved aquaculture-strength drugs for effective parasite treatment the first time, not the forth, fifth or sixth.

Antifungal treatments

These are in a category all themselves because all fungal infections are secondary to other stressors. If your fish have fungus, don’t treat the fungus, treat the main cause.

Use the money you’re saving not buying these products to do some more water changes and replace your fish food every 6 months. And if you have a fish tank, don’t keep buying filters because the package told you so!

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2 thoughts on “The Fish Products You ACTUALLY Need”

  1. What would you recommend for those of us with no veterinary team comfortable with aquatic pets nearby? Based on a quick search, the closest aquatic vet is over 100 miles away. As a previous vet tech, I understand the importance of a professionals opinion on pet health, but what do I do when one of my fish gets sick?

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