Water Hardness and its Effect on Your Fish

Map of US Water HardnessWater quality has a direct impact on the health of aquarium fish. One very important aspect is water hardness. Water hardness has major effects on pH and its stability and hence the survival of your aquarium fish.

Water Hardness And Its Effect On Fish:

Water hardness is the level of minerals present in the water. Water has so many substances dissolved in it. Water hardness is the measure of divalent metal ions present, such as calcium, magnesium, etc. The most common mineral present in water is calcium.

The hardness of water depends on the source of your water, for example, water from wells with lots of limestone is hard. Water coming from lakes and rainwater largely lack these minerals and are thus categorized as soft water.

Hardness of water is of the following two types: permanent hardness and alkalinity.

It should be noted that the water hardness affects the pH scale of the aquarium water. Hard water has comparatively higher pH and this will be alkaline. The type of water needed depends on the species of the fish; as each species has its preferred range of water hardness. Most average water from our tap can support the life of tropical fishes.

It is important to know the hardness requirement of your fish. Water hardness affects fish health owing to osmoregulation factor. Some common fish disease treatments are affected by water hardness and hence needs to be considered while calculating dosages.

Aquarium water hardness can be decreased.

1. Reverse osmosis: the most economical and popular way to soften the aquarium water is Reverse Osmosis Unit. The heavy minerals, contaminants, and metals are removed from the source.

2. Water softening pillows: there are a number of manufacturers of these and it can be added in our aquarium filters. These pillows work well for the smaller aquariums but do not do that well in case of large water tanks. There are also the types of pillow softeners that can be recharged and reused.

3. Peat: it is often used to keep the water soft for the tropical fish. There are many methods to use peat. It can be used in an aquarium filter, or it can be soaked for a couple of weeks in a larger bucket. Also, it can be put in a pillowcase and then submerged in a bucket.

4. Rainwater: pure rain water is preferred by many tropical fish. If rainwater is used for this purpose, it should be assured that it has come from a location with clean air quality. Chemical leaching should be prevented by using clean collection methods and proper plastics.

5. Driftwood: Aquarium water is also softened by the addition of driftwood. It is often used in smaller pieces, first boiled and when cooled scrubbed to remove impurities if any. If the driftwood is just soaked the aquarium, water needs to be changed daily. Driftwood changes hardness the least of all these methods.

The water hardness can be increased when needed.

1. Crushed coral: this greatly helps to increase the aquarium water hardness. It can either be added to the filters or as substrate instead of gravel.

2. Buffer products: they ensure the rise of GH and KH while the pH of the water is maintained.

3. Limestone: Limestone allows calcium and other minerals to leach out into the water column and hence increase the water hardness.

Consequences of putting a hard water fish in soft water.

It is a paradox that while a few hard water fishes can adapt to live in soft water, most of the hard water fishes often fail to thrive in soft water and the more acidic conditions. Soft water contains few dissolved minerals, thus the alkalinity reverse is very low. It shows faster and more severe drops in pH, unlike hard water.  It is worse to have wild pH swings than it is to have a pH that is not ideal.

Fish which are not adaptable to the rapid changes in pH, or if the pH drops below 6.0, can result in the damage of gills and skin, respiration problems, and ultimately death. Plus the soft water is deficient in many minerals and if the particular hard water fish fails to get them, it may lead to their health degradation, so an addition of mineral supplements may need to be done.

Consequences of putting a soft water fish in hard water.

For the small fish which are adapted to live in the soft water conditions, it is possible that when they come in contact with the minerals in hard water they may suffer from blockages in some organs and damaged kidneys. Since they fail to adapt to the hardness of the water and the many types of minerals they fail to breed and their life span gets reduced. Although depending on the species of the fish, many of them might adapt to the hardness but successful breeding won’t happen as the thick egg shells won’t adapt to hard water.

Therefore, it is crucial to know the type of water conditions which are optimum for the fishes you breed and to maintain these conditions for their healthy survival.  When setting up a community tank pay close attention to the water hardness requirements and choose fish with similar needs.  Simple details like these can make a huge difference between keeping fish and having fish that thrive.

By Jagriti Gulyani

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