Top 20 Frequently Asked Questions
by Dr. Erik Johnson
Ashland VA Aug 10-11 2003 [?]
• Half of the questions are about a fish symptom.
• The other half occur through several categories.
• Hundreds of questions are asked every day.
#20 Does ___ Kill Frogs and Snails?
• Dimilin does not.
• Formalin kills snails and tadpoles, not frogs.
• Potassium kills snails, some tadpoles, not frogs.
• Salt can kills some snails, others survive. Tadpoles and frogs survive.
#19 Should a Pond Have Gravel on the Bottom?
• Hell no.
• Accumulation of detritus, solid wastes, causes proliferation of hazardous bacteria.
• Production of noxious gases like hydrogen sulfide and methane.
#18 How Can You Tell Boy From Girl Koi?
• Males have breeding tubercles on their gill covers and pectoral fins in springtime, even in pre-mature males.
• Females are perfectly smooth on the pecs.
• Females are rounder in conformation viewed from the top. Males are streamlined even when heavily fed.
#17 How Do You Measure Salt Levels?
• There are three ways. You can drill out a SeaTest hydrometer. It’s hard.
• You can run a salt level test, they’re cheap and effective and accurate.
• You can use an electronic salinity meter. Easiest.
#16 What Kind of Pump Should I Use?
• Submersible pumps are easy to install. They run well and they can move up to 3900 gph.
• External pumps are longer lasting and can be more energy efficient. Parts are available for external pumps. Shock hazards are reduced. They don’t clog up because of the leaf trap which is easy to clean.
• Wisdom of the pump sock. (Defeats pump).
#15 What Should I Do About Herons?
• Heron decoys usually don’t work and may attract other herons.
• Gator head works.
• Scarecrow works.
• Netting works well.
• Trip lines don’t work.
#14 Do Frogs and Birds Carry Fish Parasites?
• No, it’s the LEAST likely mode of transmission.
• Can it happen? Yes.
Does it happen, rarely.
• Parasite must resist drying or be abundant to be carried in water droplet.
NOT in stools or urine.
#13 Can Koi and Goldfish Breed?
• Heck yeah.
• But goldfish will not allow any Koi fry to live.
• Koi WILL allow goldfish eggs and fry to survive.
• What kind of babies do you end up with in Koi x goldfish polyculture? Just goldfish.
#12 Why Didn’t Bug-b-gone Work?
• Usually, it’s because it may be a poor dose, or not strong enough.
• Just as often, the person is treating a crashed pH (untested) with parasite remedy.
• Sometimes the medicine is defeated by UV, carbon, filtration, organics.
#11 My Goldfish and Koi Are Chasing Each Other
• Usually they are spawning.
• If water quality is good, the fish will heal.
• If it’s not they will ulcerate.
• If the female is outnumbered, she could die.
• Pond should not have sharp rocks at edge!
#10 Red Worms in the Filter!
• Tubifex or bloodworms.
• Carry no pathogens for Koi.
• Carry myxobolus for salmonids!
• Eaten on sight, which is why they only exist in filter.
• What if we applied copper?
#9 Food & Storage, What’s Right?
• Best food has fish or shrimp meal as first ingredient
• Less corn and less plant protei• is better.
• Avoid ingredient splitting.
• Look for stabilized vitamin C
• Refrigerate, do NOT freeze the food.
#8 What’s the Best Way to Prepare for Winter?
• Make sure the waterfall is off at night and when temps are dropping
• Never put fish to “bed” with leaves and solids on pond bottom
• Salt at end of year.
• Do not disturb bottom-most level of water
• Keep a hole in the ice with a cattle trough heater.
• Feed Cheerios and wheat germ in the Fall for fish and filter.
#7 Should I Do Water Changes in My Pond?
• Common question
• Topping off is not a water change
• 20% every two weeks.
• 75% every 2-3 months
• Always dechlorinate
#6 Should I run a UV and pump all Year?
• Run the pump all year. In winter, be careful about the bottom limnion and supercooling.
• Run the UV as needed to control algae.
• UV kills “good” microorganisms in water too, including bacteriophages.
• Spare the bulb and run it in the Spring.
#5 How many fish can I keep in my pond?
• There are lots of numbers
• I like: “One inch of fish per ten gallons of water.”
• One inch of fish per square foot of surface area if you have little or no filtration.
#4 Is String Algae bad? Solutions?
• String algae is good.
• All algae is good
• Consumes O2 at night
• String algae kills pumps and flows
• Control with ONE Plecostomus
#3 What can I do about green water?
• Major water change to eliminate nitrates
• Shade the pond
• Reduce feedings
• Deploy a veggie filter
• Employ a UV sterilizer.
#2 My Ph Is High. How Can I Bring It Down?
• Don’t.
• Unless Ammonia is “up” then be cautious about having it higher than neutral.
#1 My Fish is Sick, What’s Wrong with It?
• #1 All Time Most Common Question
• Useless, too.
• Need Checklist info. [See pg 16]