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How a New Fish is Like a Canary -- Why New Fish Die First

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How a New Fish is Like a Canary -- Why New Fish Die First image

Best Aquarium Fish to Buy in October 2025

1 500 Freshwater Aquarium Fish: A Visual Reference to the Most Popular Species

500 Freshwater Aquarium Fish: A Visual Reference to the Most Popular Species

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500 Freshwater Aquarium Fish: A Visual Reference to the Most Popular Species
2 Marineland Portrait Glass LED Aquarium Kit, 5 Gallons, Hidden Filtration,Black

Marineland Portrait Glass LED Aquarium Kit, 5 Gallons, Hidden Filtration,Black

  • SLEEK DESIGN OFFERS 360° VIEWING WITH CLEAR GLASS AND ROUNDED EDGES.
  • CREATE AMBIANCE WITH DAZZLING DAYLIGHT AND SOOTHING MOONLIGHT LEDS.
  • EASY ACCESS FOR MAINTENANCE WITH HINGED LIGHTING AND SLIDING CANOPY.
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Marineland Portrait Glass LED Aquarium Kit, 5 Gallons, Hidden Filtration,Black
3 Weewooday 7 Pieces Artificial Fish Colorful Fake Fish Glowing Effect Aquarium Decor Floating Ornament for Tank Decoration(Classic Color)

Weewooday 7 Pieces Artificial Fish Colorful Fake Fish Glowing Effect Aquarium Decor Floating Ornament for Tank Decoration(Classic Color)

  • VIBRANT, COLORFUL FISH CREATE A CHEERFUL UNDERWATER ATMOSPHERE.
  • DURABLE SILICONE ENSURES LONG-LASTING BEAUTY IN YOUR FISH TANK.
  • ADJUSTABLE INSTALLATION FOR EASY SETUP IN ANY AQUARIUM TYPE.
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Weewooday 7 Pieces Artificial Fish Colorful Fake Fish Glowing Effect Aquarium Decor Floating Ornament for Tank Decoration(Classic Color)
4 Aqueon Aquarium Fish Tank Starter Kit with LED Lighting 10 Gallon Fish Tank

Aqueon Aquarium Fish Tank Starter Kit with LED Lighting 10 Gallon Fish Tank

  • ALL-IN-ONE KIT: EVERYTHING YOU NEED TO START YOUR AQUATIC JOURNEY!
  • VIBRANT LED LIGHTING ENHANCES THE BEAUTY OF YOUR AQUARIUM SETUP.
  • EASY MAINTENANCE WITH FLASHING FILTER INDICATOR AND PRESET HEATER.
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Aqueon Aquarium Fish Tank Starter Kit with LED Lighting 10 Gallon Fish Tank
5 API TAP WATER CONDITIONER Aquarium Water Conditioner 16-Ounce Bottle

API TAP WATER CONDITIONER Aquarium Water Conditioner 16-Ounce Bottle

  • NEUTRALIZES HARMFUL CHEMICALS FOR SAFE FISH HABITAT.
  • SUPER STRENGTH FORMULA FOR OPTIMAL WATER SAFETY.
  • EASY DOSING: 1 ML PER 20 GALLONS FOR QUICK USE.
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API TAP WATER CONDITIONER Aquarium Water Conditioner 16-Ounce Bottle
6 Marina LED Aquarium Kit, 10 gallon

Marina LED Aquarium Kit, 10 gallon

  • COMPLETE SETUP FOR EASY AQUATIC HOME CREATION!
  • EFFICIENT MARINA SLIM S15 FILTER WITH QUICK-CHANGE CARTRIDGES.
  • PERFECT SIZE: 10-GALLON FOR ANY SPACE, 20L X 10W X 12.5H!
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Marina LED Aquarium Kit, 10 gallon
7 Encyclopedia of Aquarium and Pond Fish (DK Pet Encyclopedias)

Encyclopedia of Aquarium and Pond Fish (DK Pet Encyclopedias)

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Encyclopedia of Aquarium and Pond Fish (DK Pet Encyclopedias)
8 Tetra ColorFusion Aquarium 20 Gallon Fish Tank Kit, Includes LED Lighting and Decor

Tetra ColorFusion Aquarium 20 Gallon Fish Tank Kit, Includes LED Lighting and Decor

  • CUSTOMIZE YOUR AQUARIUM WITH VIBRANT, CUSTOMIZABLE LED COLORS!
  • ANEMONES PROVIDE A COZY HIDING SPOT FOR YOUR FISH TO RELAX.
  • COMPLETE KIT INCLUDES EVERYTHING YOU NEED FOR A STUNNING SETUP!
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Tetra ColorFusion Aquarium 20 Gallon Fish Tank Kit, Includes LED Lighting and Decor
9 PAIZOO Fish Tank Digital Thermometer Accurate LED Display to ±0.9°F Tank Thermometer Aquarium Temperature Measurement Suitable for Fish, Axolotl, Turtle or Aquatic

PAIZOO Fish Tank Digital Thermometer Accurate LED Display to ±0.9°F Tank Thermometer Aquarium Temperature Measurement Suitable for Fish, Axolotl, Turtle or Aquatic

  • VIVID LED DISPLAY: EASY-TO-READ TEMPERATURE FROM ANY ANGLE, DAY OR NIGHT.

  • CORDLESS & TOUCH ACTIVATION: NO MESSY WIRES; QUICK TEMPERATURE READING WITH A TOUCH.

  • HIGH ACCURACY: ACCURATE READINGS FROM 0-140°F, REFRESHES EVERY 5 SECONDS.

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PAIZOO Fish Tank Digital Thermometer Accurate LED Display to ±0.9°F Tank Thermometer Aquarium Temperature Measurement Suitable for Fish, Axolotl, Turtle or Aquatic
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ONE MORE?

Whenever a fish is netted, bagged and shipped (or driven home) it is a highly stressful adventure for him. He loses his immunity to disease for about 72 hours after the trip. He is weaker than another fish that has not suffered through the same ordeal. During this stressful 72-hour period his general health and body system is at a critical low point.

If, during this 72-hour period, he is exposed to parasites, other fish with health problems, unhealthy water quality and/or he has an underlying health problem of his own his chances of overcoming any of these obstacles are slim – much slimmer than that of another fish who has been “at home” in the pond for many weeks or more. Because of this it is wrong to assume “the new fish” is the culprit of any gill disease or parasitic conditions even if ALL the new fish died and the others are still alive.

Here’s a fine example:

Recently a customer purchased a number of new fish from us. Within a week every one of the new fish had died or were suffering. Naturally our first inclination was to say that something was wrong with the new fish. Upon examining a live fish from the customer’s pond we found gill flukes – a particularly nasty parasite that can only be detected through a microscope. Again – the natural inclination was to blame the new fish since they all died or were sick. Surely the new fish must have had gill flukes when the customer took it home.

We are particularly careful about quarantining and treating all our stock before they go out our door and it literally shocked me to think that we could have sold a customer a fish with gill flukes! In cases like this the first thing we have a mucus scraping performed on a fish from the same batch. It did not surprise me to find no gill flukes at all.

Then why was my customer losing only the new fish and the others seemed fine?

The others were, indeed, in trouble though it appeared at the time nothing was wrong with them. These new fish were like the canaries the miners used to carry down into the mines with them. If the air quality was bad the canary died and the miners knew they could not stay inside the shaft. These new fish were frail and died first. In this case our customer did the right thing by reacting quickly by treating his pond and killing the flukes before they could wear down the stronger fish.