Seachem Focus is a unique over-the-counter aquarium product that serves primarily as a binding agent for mixing other medications into fish food. It is a polymer-based binder with mild antibacterial activity (nitrofurazone-based) that, when mixed with food and a complementary medication such as Seachem KanaPlex or MetroPlex, keeps the active ingredient bound to the food and prevents it from leaching into the water. This allows for highly targeted delivery of antibiotics or antiprotozoals directly to the fish’s gut — a far more effective approach for internal infections than water dosing. Focus is an OTC aquarium product, not a prescription-grade veterinary medication. For valuable fish, consult an aquatic veterinarian.

Overview

Water dosing is effective for external disease and for antibiotics that are absorbed through the gills, but for internal bacterial infections, hexamita, tapeworms, and similar gut pathogens, delivering medication directly via food is far more effective. The challenge is that most water-soluble medications quickly dissolve off food and into the water, losing most of their potency. Seachem Focus solves this by binding the medication to the food, dramatically improving the fraction of active ingredient that actually reaches the fish.

Uses

  • Binding agent for mixing KanaPlex, MetroPlex, Sulfaplex, and other Seachem medications with food
  • Delivery of antibiotics for internal bacterial infection
  • Delivery of metronidazole for hexamita and hole-in-the-head disease
  • Mild standalone antibacterial food additive
  • Feeding sick fish that are too weak for water treatment alone

Dosage

  • Standard mixing ratio: 1 measure of Focus plus 1 measure of the intended medication per tablespoon of food
  • Duration: Feed the medicated food for 5 to 10 days, or as recommended for the specific infection
  • Food types: Works with flake, pellet, and frozen food (thaw frozen food first)

Always follow the product label for exact ratios.

Safety Considerations

  • Reef-safe — Because it is bound to food rather than dissolved in water, Focus has minimal impact on invertebrates and corals
  • Invertebrate-safe — Generally safe for shrimp, snails, and corals at label dose
  • Scaleless fish — Safe because the delivery is via food
  • Fish must be eating — Focus is only useful for fish that are still willing to eat. Sick fish that have stopped eating cannot be treated this way.
  • Use with complementary medications — Focus alone has limited antibacterial activity; its primary value is as a delivery vehicle for other treatments
  • Storage — Keep the powder dry and tightly sealed

Water Chemistry Effects

  • Minimal effect on water chemistry because medication is bound to food
  • Some leaching may occur during feeding, but much less than direct water dosing
  • Does not affect pH, hardness, or biological filter
  • Compatible with activated carbon (carbon does not need to be removed)

How to Use

  1. Measure an appropriate amount of the fish’s normal food (flake, pellet, or thawed frozen)
  2. Add one scoop of Focus
  3. Add one scoop of the medication you wish to deliver (KanaPlex, MetroPlex, etc.)
  4. Add a few drops of tank water or Seachem Garlic Guard to make a paste
  5. Let the mixture sit for 5 to 10 minutes to fully bind
  6. Feed to the fish
  7. Repeat 1 to 2 times daily for the recommended treatment duration
  8. Observe whether sick fish are actually eating the medicated food — if not, switch to water dosing

FAQs

What medications can I mix with Focus? KanaPlex, MetroPlex, Sulfaplex, NeoPlex, and similar Seachem aquarium medications. Other medications can sometimes be used too.

Is it safe for reef tanks? Yes, because it is delivered via food rather than dissolved in the water column.

Can I use it alone? Focus has mild antibacterial activity on its own but is primarily designed as a delivery vehicle for stronger medications.

What if my fish won’t eat? Focus is only effective when fish eat the medicated food. If fish are anorexic, use water dosing instead.

Does it affect my biological filter? No, because it is bound to food and stays in the fish’s gut rather than the water column.

Can I use it with any fish food? Yes, it works with flake, pellet, and frozen foods. Thaw frozen food before mixing.

How much medicated food do I feed? Normal feeding amounts; overfeeding medicated food will not speed recovery and may pollute the tank.