How to Save a Sick Fish

sick fish

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If your fish is presenting any physical or behavioral signs of illness, don’t wait around for them to magically get better! Follow these steps for the best chance to save your sick fish.

Step 1: Check Your Water Quality

Poor water quality is the #1 cause of illness and disease in fish. Like the air we breathe, the water a fish swims in is critical to good health. Use a liquid-based test kit, not those silly strips, and see if your parameters fall within the following ranges. For those species not listed, we recommend looking up their parameters here.

Goldfish (indoors & outdoors)

Parameter Range
Ammonia ≤ 0.1 mg/L (ppm)
Nitrite 0 mg/L
Nitrate < 20 mg/L
pH 6.5-9.0
kH (alkalinity) > 100 mg/L
gH (hardness) > 100 mg/L
Temperature 32-85F (0-29C)

Koi

Parameter Range
Ammonia ≤ 0.1 mg/L (ppm)
Nitrite 0 mg/L
Nitrate < 20 mg/L
pH 6.5-9.0
kH (alkalinity) > 100 mg/L
gH (hardness) > 100 mg/L
Temperature 32-85F (0-29C)

Betta

Parameter Range
Ammonia ≤ 0.1 mg/L (ppm)
Nitrite 0 mg/L
Nitrate < 20 mg/L
pH 7.0-8.5
kH (alkalinity) > 100 mg/L
gH (hardness) > 100 mg/L
Temperature 78-82F (25-28C)

General Tropicals

Parameter Range
Ammonia ≤ 0.1 mg/L (ppm)
Nitrite 0 mg/L
Nitrate < 20 mg/L
pH 7.0-8.5
kH (alkalinity) > 100 mg/L
gH (hardness) > 100 mg/L
Temperature 78-82F (25-28C)

Please keep in mind these are general guidelines – not all fish read the book!

Step 2: Fix Your Water Quality

If your ammonia, nitrite or nitrate are too high, such as those tanks undergoing New Tank Syndrome, you can take immediate steps to fix this. Chronic stress causes a decreased immune function, keeping your sick fish ill. If you are repeatedly replacing your filter media, you are resetting your biological filtration! Stop replacing your filter media!

If your pH or temperature is out of range, DO NOT MAKE FAST CORRECTIONS. This will cause your fish to DIE. In order to correct issues with pH and/or temperature, make very small changes over days to weeks to ensure your fish will survive. This is the case for Old Tank Syndrome and fish in temporary holding tanks during deep cleanings.

Most of the time, these two steps will take care of most fish issues.

Step 3: Check Your Fishes’ Food

Is that the same container of food you bought when you brought your fish home 2 years ago? Chances are your fish hasn’t been getting enough vitamins in order to have a healthy immune function. Once you open ANY type of fish food container, you have 6 months to feed it out and then TOSS IT. Most bettas will never finish a full container of betta food.

Be sure to properly store your fish’s food in an airtight container in a cool, dark area of your home. Never store fish food outside!

For more help on what to feed your fish, click here.

Step 4: Call Your Veterinarian About Your Sick Fish

Sure, you could go to the pet/koi store and buy a bunch of medications that might work, or you can get to the bottom of your fishes’ disease and get them treated quickly. We broke down the cost of DIY vs. professional so you can see what your time and money are worth. Yes, a specialty veterinarian, especially a house call one, is a premium service and can carry a larger price tag. We wish more veterinary schools taught their students enough to handle fish properly. But wasting time on worthless OTC medications can make the problem worse before your veterinarian gets there.

To find a fish veterinarian, follow these steps.

To some of you, your fish may not be worth the cost of a veterinarian. We’re very sorry to hear that, and understand that is your choice. For those of you who understand the commitment of bringing a fish into your home, we’re here to help.

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11 thoughts on “How to Save a Sick Fish”

    1. Fish owner newbie

      Sick fish
      Loss of appetite.
      Weakness or listlessness.
      Loss of balance or buoyancy control, floating upside down, or ‘sitting’ on the tank floor (most fish are normally only slightly negatively-buoyant and it takes little effort to maintain position in the water column)
      Erratic/spiral swimming or shimmying.

  1. Hi my fish is betta female is laying on side now. Almost upside down she is still alive but looks Very sick. My kid Savannah got it from pet smart in newburgh NY. She named her christine. What’s wrong with her fish?

  2. My fish is doing catvill again and again in water and is lying still in water pls tell an idea so that she can survive.I need an idea urgent and also she is not eating fish food I need idea today

  3. Pingback: How do you save a dying guppy – GlobeAqua

  4. Pingback: Top 10+ How To Know If A Fish Is Dying - GA Pet Sitters

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