The oceans, rivers, lakes and backyard ponds all succumb to low dissolved oxygen fish kills. Nature has 3 ways which it oxygenates water: direct diffusion, wind and wave and photosynthesis. (More detailed information at the University of Florida)
On a warm summer night after a windless day is the time when the dissolved oxygen level of all waters is at its lowest. Waterfalls, cascades and fountainheads are not substitutes for aeration. Dissolved oxygen is critical to the wellbeing and survival of pond fish. Ponds where the fish are constantly under the waterfall at the surface needing more oxygen are insufficiently aerated. Different types of pond fish require different levels of oxygen.
Cichlids require more oxygen than Koi. Koi require more oxygen than goldfish and goldfish require more oxygen than plecostomus. Ponds that are highly aerated will all have healthier fish which are subjected to less stress. It is not possible to over-aerate a pond in south Florida. A generous amount of aeration will help keep water clearer of algae and will support the aerobic bacteria count. The aerobic bacteria (the good bacteria) is paramount to the overall wellbeing of the pond’s inhabitants.
Whenever a pond is under-aerated, the aerobic bacteria will be less and the anaerobic bacteria (the bad bacteria) will thrive. The anaerobic bacterias: Aeromonus and Pseudomonus are harmful and if left unchecked: deadly to pond fish.
Dissolved oxygen is measurable. The lowest levels always occur just prior to sunup. Once the sun comes up, the phototsynthesis process kicks in and helps raise dissolved oxygen. The higher the temperature, the lower the oxygen level. Whenever salts, or any water additives, enhancers or medications are in the water, the dissolved oxygen goes down, making it very important to have good aeration.
Good aeration requires an air pump which sits on the outside of the pond and pumps air to the pond’s bottom where the air is diffused with a good airstone allowing tens of thousands of fine bubbles per minute to raise from the bottom up to the surface. There are no ways of moving water which duplicate this type of system and its effectiveness to raise oxygen. Aerators are quiet, use extremely low levels of energy and when used with a high quality airstone will be of great value to your pond and its inhabitants.
An aerator is automatically an emergency backup system should your pump or filter fail. You have days of worry-free life support for your pond. Pond fish can go without food and filtration for several days, however, if the oxygen level is too low, they simply die. It cost less to put a good aeration system on your pond than it does to have an expensive fish doctor come out and check your dissolved oxygen level. Finally if your pond is aerated, the” silent killer” will not be present in your pond.
Duboisi is your best choice in algae-eating fish. This algae-eating fish eats algae all day and is very visible. If you should run out of algae, they will happily accept pellets or flake food.In addition, the Duboisi have the capability for reproduction and will supply you with algae-eating warriors. Duboisi babies are the most attractive of all freshwater baby fish (black with white spots).
Along with spring comes Bufo toad season. Their ability to reproduce in your pond can cause several problems:
1. Alll stages; egg and tadpoles are toxic to fish.
2. These eggs and tadpoles create water quality problems and
3. The Bufo toads overpopulation allows them to become a future problem for your pond and yard.
Your best defense against the Bufo Marinus toad eggs and tadpoles is an African fish called Venustus. The Venustus is highly resistant to the toxins due to their short intestinal tracts and very efficient at greatly reducing the numbers of hatching eggs and tadpoles.