Fish Flex (Fix Flex) Cephalexin 250mg & 500mg Fish Antibacterial

If you previously purchased Thomas Labs Fish Flex, Fish Flex Forte, Aqua Ceph, Aqua Flex or FISHBIOTIC Cephalexin, here is what has changed and what remains the same:

• Bacterial Support for Fish and Birds

  This treatment provides cephalexin coverage for aquarium fish and pet birds. It helps manage common problems such as fin and tail rot, skin ulcers, infected wounds, red patches and early signs of bacterial stress when used as directed.

• Made in the United States

  Fix Flex is made in the United States by Aqua Soma Labs. Domestic production supports consistent capsule quality from batch to batch, which matters when you are treating fish or birds in a hospital tank or cage.

• Two Strengths to Match Your Tank

  Use 250 mg capsules for smaller aquariums, hospital tanks or lightly stocked systems, and 500 mg capsules for larger volumes or when higher total amounts are needed, always following the label directions.

• Consistent Capsules

  Each capsule delivers a consistent amount of cephalexin, making it easier to scale treatment from a single quarantine tank up to larger community aquariums, lofts or aviaries without complicated calculations.

• Easy to Use

  These capsules can be opened and the powder dissolved directly in aquarium water or mixed with soft food, providing flexible options for shy, stressed or hard-to-handle fish and birds while minimizing handling and extra stress.

• Works in Freshwater, Saltwater & Aviary Setups

  Hobbyists reach for this treatment in both freshwater and marine systems, and as a convenient option for pigeons and other ornamental birds kept in lofts, cages or aviaries when an antibacterial treatment is appropriate.

• Good for Hospital Tanks and Quarantine

  Using this treatment in a separate hospital tank or treatment cage helps protect the main aquarium's biofilter and reduces unnecessary exposure of healthy tank mates or flock members while you focus treatment where it is needed most.

Directions for Use:

1. Set Up a Separate Treatment Area

   Move affected fish to a dedicated hospital tank and, where practical, house birds needing treatment in a small treatment cage. This helps protect healthy tank mates or flock members and lets you control the amount more precisely.

2. Choose the Right Strength

   These cephalexin capsules are available in 250 mg and 500 mg strengths. Select the strength that matches your aquarium volume or your professional's advice, and follow the product label for the number of capsules and how often to use it. Do not increase the amount or shorten the intervals on your own.

3. Directions for Fish Aquariums

   Add one dissolved 250 mg dose per 10 gallons (38 L) of water. Open the capsule, stir the powder into a cup of aquarium water, then pour it evenly around the hospital tank. Repeat every 24 hours with a partial water change between treatments for 5 to 10 days, and discontinue use if there is no improvement after 5 days. See the chart below for common tank sizes.

4. Use in Pet Birds (Under Veterinary Guidance)

   Only give this treatment to pigeons and other pet birds under the direction of an avian veterinarian. Your vet can advise you on the correct amount for the bird's weight, frequency and duration. Capsule contents may be mixed into soft food or drinking water exactly as instructed.

5. Maintain Water Quality & Finish the Treatment

   Perform partial water changes as needed between doses to keep ammonia and nitrite low and ensure good aeration in the hospital tank. Continue treatment for the full recommended number of days even if fish or birds appear better; stopping early can allow symptoms to return. If there is no improvement after several days, or if signs worsen, consult an aquatic or avian professional.

These figures follow the Fix Flex product label: add one dissolved 250 mg dose per 10 gallons (38 L) of water, repeat every 24 hours with a partial water change between treatments for 5 to 10 days, and discontinue use if there is no improvement after 5 days. Dose by the water volume of your treatment tank, not by the number of fish, and round to the nearest practical capsule. The bottle label or your aquatic veterinarian takes priority over this quick-reference chart.

What to Expect During Treatment

Pro Tip: Always quarantine infected fish and birds away from healthy companions during treatment to reduce stress and help prevent the spread of disease. A small, dedicated hospital tank with a heater, air stone and no substrate makes dosing and water changes easier.

Fix Flex supplies cephalexin at 250 mg or 500 mg per capsule. It works against a range of Gram-positive bacteria and some Gram-negative species that affect the skin, fins and soft tissue of fish and birds, helping to slow or stop their growth.

Each capsule is a hard gelatin shell that holds the cephalexin powder, along with standard ingredients that hold the capsule together and help the contents disperse evenly when dissolved in aquarium water or mixed with soft food.