How to Buy Healthy Fish at the Pet Store

Introduction

The difference between a healthy fish purchase and a disaster often comes down to the two minutes you spend looking at the tank before you point and say "that one." Sick fish can be bought at even the best fish stores because stress, shipping, and crowding take a toll, and pathogens can arrive in any shipment. But a healthy eye for evaluating fish before purchase dramatically reduces the odds of bringing a problem home.

Quick Overview

Evaluate the Store Before You Evaluate the Fish

The quality of a fish store tells you a great deal about the quality of the fish inside it. Before you even look at individual fish, take a few minutes to observe the store itself.

• Are the tanks clean? Some algae is normal and harmless, but tanks with visibly fouled water, heavy detritus on the substrate, or dead snails and decorations covered in waste suggest neglect.
• Are the fish in the display tanks active and healthy-looking? A tank full of listless, clamped-fin fish is a warning sign regardless of which tank you plan to buy from, since stores often share filtration systems.
• Are there dead fish in the tanks? One or two dead fish in a large store is not automatically alarming; multiple dead fish, especially in the tanks housing the species you want, warrants concern.
• Does the staff seem knowledgeable? A quick question about the care requirements of a species you are considering will tell you a great deal about the store's expertise.

Signs of a Healthy Fish

When looking at individual fish, you are looking for a combination of active behavior, normal posture, and physical integrity.

• Active and swimming normally: a healthy fish swims with purpose, exploring the tank, interacting with tankmates, and responding to stimuli. Hovering in one spot, hiding constantly, or drifting near the surface (without being a surface-breather by nature) are warning signs.
• Fins held open: fins clamped close to the body are the single clearest universal sign of stress or illness. Look for fins that are erect, spread, and undamaged.
• Good body condition: the fish should look well-fed and proportionate. A pinched belly suggests parasites or starvation. A bloated, pinecone-scaled fish suggests dropsy.
• Clear eyes: eyes should be clear and symmetrical. Cloudy, sunken, or protruding eyes are signs of disease or injury.
• Intact skin and scales: no white spots, no fuzzy patches, no sores, no missing scales, no reddening at the base of fins.
• Normal breathing: gill movement should be slow and regular. Rapid gill movement, gasping, or one-sided gill operation indicates stress, parasites, or ammonia exposure.

Red Flags to Walk Away From

• White spots: small white dots like grains of salt on the body or fins are classic ich. Do not buy from this tank, and be cautious about other tanks on the same filtration system.
• Gold dust coating: a fine golden shimmer on the body suggests velvet (Oodinium), which is highly contagious and fast-moving.
• Frayed or ragged fins: fin rot indicates bacterial infection, often related to poor water quality in the store tanks.
• "Do not sell" tags on tanks: some stores tag tanks under observation or treatment; this is a good sign of responsible management, but buy from other tanks that day.
• Fish that will not eat during feeding demonstrations: ask the store to feed the fish; healthy fish respond eagerly to food.

If you see one sick fish in a tank, assume every fish in that tank has been exposed. Even if other fish look healthy, they may be in the incubation period of the same disease. Quarantine is especially important after buying from any tank with visible illness.

Questions to Ask the Store

• When did these fish come in? Fish that arrived within the past week are higher risk; those that have been eating and thriving for two or more weeks are safer.
• Have any fish in this tank been treated recently, or are any tanks currently under medication?
• What are you feeding them, and how often? Confirm you can match the diet.
• Are these tank-raised or wild-caught? Wild-caught fish are more likely to carry internal parasites and may need more careful acclimation.
• What water parameters do you keep these fish at? Knowing the store's pH and hardness helps you acclimate the fish to your conditions gradually.

Acclimating New Fish

Even perfectly healthy fish experience stress during transport, and going from store water to your tank water abruptly adds osmotic stress on top of that. Take fifteen to twenty minutes to acclimate new fish before releasing them.

• Float the sealed bag in your tank for fifteen minutes to equalize temperature
• Cut open the bag and add a small cup of tank water to the bag every five minutes for another fifteen to twenty minutes
• Net the fish out of the bag and into the tank; do not pour the bag water into your tank (it may contain pathogens, ammonia, or heavy metals from the store)
• Turn off bright lights for an hour after introduction to reduce stress

New fish often hide for the first day or two. This is entirely normal. Give them time to explore and find their place in the tank before deciding whether something is wrong.

Online Fish Buying

Buying fish from reputable online breeders and retailers has become increasingly common, and often produces healthier, better-quality fish than a local pet chain. Online sources can offer rarer species, specific color morphs, and fish from breeders who specialize in a single species and raise them in excellent conditions.

The risks are different from in-store buying: you cannot inspect the fish before purchase, and shipping is stressful. Buy from sellers with strong reviews, a live arrival guarantee, and who ship with insulation and heat packs appropriate to the season. Quarantine online-purchased fish just as carefully as store-bought ones.