Aquarium Bible

Proper Environment for Breeding Fish in Aquariums

Proper Environment for Breeding Fish in Aquariums
Most species require careful preparation and cosseting in readiness for reproduction if the best results are to be achieved. Some species may readily breed in a community aquarium as in nature, although its possible you will be unaware of it, because other tank mates will devour any eggs, or indeed any young that may be deposited.
Generally separate “spawning tanks” are used as the majority of aquarium fishes will require specific water conditions in order to breed successfully. Typical examples are the Cichlids of Lake Malawi or Lake Tanganyika, which require hard alkaline conditions. Conversely, species of the Characin family need soft acidic water for their eggs to hatch out.

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Temperature

An important factor is the raising of the temperature; this will induce spawning, and should remain raised for the early period of incubation and rearing of the young. In general the temperature is raised just a few degrees above the normal for a particular species. You will be able to determine specific temperatures, as well as the individual requirements for a species, when you visit that species page.

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Do You Understand Water Quality?

At this point I am assuming that you have a basic understanding of the principles of “water quality”. If this is not the case you will not have the necessary knowledge to understand such terms as “water hardness”, or “pH”, and therefore the consequences this may have on your fishes if either, or both, are not correctly adjusted. This knowledge is imperative when it comes to breeding your fishes, and I therefore suggest that you study my page on Water Quality.

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Water Conditions

In order to be aware of appropriate water characteristics you will need water hardness, and pH test kits. These should be essential pieces of “equipment” in a fishkeepers toolkit, and even more so for breeding. There are many brands of these widely available, so it’s down to individual preference. The electronic versions of these are quite expensive, but if you can afford them they are well worth it in the long run.
It is very likely that your tap water will be to hard for breeding many of the more sensitive species. If this is so you will need to soften the water, there are several ways to do this. Below is an example expressing soft to very hard:

Very Soft

0

to
50 ppm

or
0

to
2.8 ºdH

Moderately Soft

50

to
100 ppm

or
2.8

to
5.6 ºdH

Slightly Hard

100

to
200 ppm

or
5.6

to
11.2 ºdH

Moderately Hard

200

to
300 ppm

or
11.2

to
16.8 ºdH

Hard

300

to
450 ppm

or
16.8

to
25.1 ºdH

Very Hard.

450

to
+ppm

or
25.1

to
+ ºdH

The measurement for water hardness is variously expressed in different parts of the world. Most commonly used is the German formula: (ºdH), this is calculated on the principle that one degree of hardness indicates one part of calcium oxide [CaO] in 100,000 parts of water. A more accurate, and scientific term, (ppm) parts per million, is also very widely used.

To convert ppm to the German formula: ºdH……...ppm x 0.056 = ºdH
Use the calculator below to convert º dGH into parts per million (ppm)

º dGH conversion table to: parts per million (ppm)

º dGH ppm.
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If Hardness is too high:

> Make sure there are no calciferous materials in your water, i.e. rocks and gravel must be inert and not contain lime or chalk.

> Use a reverse osmosis (R.O.) unit; this will clear all the impurities out of your water, as well as softening it. The problem with reverse osmosis is that it is actually “too pure” (having removed all the minerals as well); the secret is to mix the “pure” water from the R.O. unit with dechlorinated tap water, until you get the right mix. If you start with a mix of around 60% R.O. water and 40% dechlorinated tap water, it shouldn’t be too far out, but check it yourself until its correct.

> Dilute your water with rainwater (filter it first for 24 hours through carbon), or use distilled water, and monitor, until the desired value is reached.

> Alternatively water-softening products are commercially available.

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On the other hand, If Hardness is too low:

> Add calciferous materials such as pieces of limestone into your aquarium; or a little coral gravel into your filter; don’t add too much at one time, and monitor until the desired value is reached.

It must be remembered that if alterations to hardness, and more importantly pH, are required, they must be carried out slowly This must be carried out over two or three days depending how much of a change is required, failure to observe this requirement could result in stress, or even death to fishes.

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Checking your pH

You need to be aware that pH is closely linked to water hardness; generally speaking a higher concentration of salts (the water is harder, or more alkaline) means a higher pH, and a lower concentration of salts (the water is softer, or more acidic) means a lower pH, although there can be exceptions.

Whatever the case, and even if you consider yourself to be in a soft water area, it will be unlikely that your tap water will be any where near acidic enough for spawning acid-loving fish, such as Tetras. In other words you will probably need to lower the pH of you water.

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Reducing pH

If you need to acidify the pH of water you could try using peat. Fill your aquarium with water and cover the surface with a 2-inch (5cms) layer of peat. Leave this for about a week, or until it settles to the bottom. The peat will release chemicals that will acidify the water and stain it brown, this is a more natural way to reduce the pH and the colouration of the water resembles that of rivers in and around the Amazon Basin. This seems to suit fishes in spawning condition that originate from the so-called “ Black Water Regions”.

If you consider the more natural approach to elaborate, or to slow, then you could use a commercial pH adjuster, such as Proper pHTM, this particular product sets the pH at a fixed level (you buy the pH requirement that you need, pH 7.0, pH 6.5, pH 6.0, etc.). It then holds or “buffers” the pH at that level and fights against “pH rebound”, ordinary adjusters only temporarily change pH, and water can very quickly return to its previous condition. PROPER pHTM also Neutralises Chlorine, Detoxifies Heavy Metals, adds Electrolytes, and contains Aloe Vera.

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Raising pH

> If pH needs to be raised I find that the natural and best way to do it is to use coral gravel (it is also available in sand and shell form). This will achieve two goals at the same time, both raising pH and increasing hardness. All that you need to do is to place a small amount of the coral in your filter; you must carry out this process a little at a time and keep a check on the results until the desired level has been reached.

> Again, there are commercial products available that will get you your desired result, but in the case of raising pH I think coral is the best, it is also much cheaper, a bag of coral gravel will last for years.

It is essential that you maintain a stable pH within the correct range, and the appropriate hardness, for the spawning of your tropical fish. Any changes made to the pH or hardness of aquarium water should be conducted slowly over a number of days to avoid stressing any fish.

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As a general guide, for spawning,

Egg-Laying Fish, e.g.

> Tetras,

> Angelfish

> Rasboras… prefer pH 5.0 - 6.0, Soft Water; 1º - 2ºdH, Temp; 75ºF (24ºC)

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While the Livebearing Species e.g.

> Mollies,

> Swordtails and

> Guppies… prefer pH 7.0 - 8.0, Slightly Hard Water; 5º - 20ºdH, Temp; 75ºF (24ºC)

*These are general guidelines and each species requirements should be checked specifically.

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Change the Water

It is very important that partial water changes are carried out for the health and well being of your young fish’s. There will be minimum filtration in the rearing tank, usually just a bubble-up sponge filter, which will provide gentle filtration. Water changes will ensure that pollutants are removed. Initially change 10% of the water once a week, increase the amount as the fry grow, gradually stepping this up to 50% per week. The replacement-dechlorinated water must have the same pH, hardness, and temperature as the aquarium water that it is replacing.
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