This is one of the most common questions regarding betta fish care. We drink tap water, and we’re fine, so of course it’s safe, right? Even our dogs and cats drink it, so why shouldn’t our fish drink it?
In terms of most city tap water, it is unsafe to keep betta fish in. For the most part, it is unsafe to keep any fish in straight tap water. That being said, treated tap water is entirely safe for fish and most invertebrates you may keep. We will discuss why tap water is unsafe (chlorine chloramines ammonia), how to treat tap water, unsuitable tap water, flushing tap lines, and well water.
The primary reason that tap water is unsafe for fish is the way in which we clean it. We normally use chlorine to sterilize the tap water and kill bacteria. This keeps us safe from bacteria and the amount used is too little to affect us.
Fish, on the other hand, are constantly swimming in it and breathing it in. The concentration used in tap water is too much for their little bodies. When betta fish swim in straight tap water, it is comparable to a watered-down bleach bath, since bleach is chlorine. This burns them both on the outside and the inside, damaging their sensitive gills and organs.
Chloramines are another potential danger found in tap water. Chloramines are a new type of sterilizer, and this is bonded chlorine and ammonia. Chlorine will gas off from the water after about 24 hours, but chloramines will stay in the water for days. These tend to be even more harmful than chlorine, since they also release ammonia into the water.
-Ammonia is another concern when it comes to tap water. While most tap water will have either chlorine or chloramines, not all tap water has ammonia. Ammonia is another cleaning component but is highly toxic to fish. It exists in most un-cycled aquariums as a by-product of fish waste breaking down.
Ammonia poisoning is one of the most common killers of betta fish because they normally live in un-cycled tanks. Like chlorine, ammonia will burn the fins, scales, eyes, and gills of a betta fish. The scales may fall off or turn black, and the same goes for the fins. Tap water may also contain trace amounts of heavy metals in a concentration safe for us, but not for fish.
Treating Tap Water
The good news about these problems is that commercially available products can easily remedy all of them. “Water Conditioners” come in all sizes, shapes, smells, and benefits. Some bind heavy metals and render these harmless, some replenish the slime coat, and some even make ammonia harmless.
If you know for a fact that your water contains only chlorine in terms of dangers listed above, you will not need a water conditioner. Chlorine alone will gas off water after a certain amount of time. The normal time is 24 hours, but you can reduce the time by adding a bubbler.
The bubbler will create ripples on the surface, which increases the surface area of the water. The greater the surface area, the faster the chlorine will escape. Keep in mind that when chlorine is removed, and oxygen is added, the pH can rise slightly. This should not be a major concern, but if the pH of your tank is higher than your tap water pH, this is a likely cause.
If you have an injured fish, with a simple tear fin or other minor injury, there are specific water conditioners for that. Not only will they remove chlorine and chloramines, but they will help your fish’s slime coat as well. Stress Coat is an example of this, as it contains aloe, which can act as an artificial slime coat and it can neutralize some heavy metals.
In terms of the strongest, and potentially most useful, water conditioner, your best bet would be Seachem Prime. This water conditioner removes the most heavy metals and can neutralize 2ppm ammonia and nitrite. You can overdose it up to 5x safely, while most other water conditioners do not have this option. This is very useful when cycling a tank.
Unsuitable Tap Water
Some tap water will be unsuitable for bettas no matter what water conditioner you use. This primarily applies to tap water with a pH above 8.0 or too many heavy metals. Water conditioners can only neutralize so many heavy metals, and some tap water just has too much.
Sometimes the exact component that makes your tank unsafe is unknown. If you have fish deaths despite perfect parameters, (ammonia 0, nitrite 0, nitrate <20) then your water could be unsafe. In these instances, there are only two possible solutions.
The first solution is to get a different water source. You can do this one of two ways. The first is to get jugs of spring water from your local grocery store. The water cannot be RO or DI (reverse osmosis or distilled) as it contains no minerals. Fish, like us, need minerals to function, and fish often draw theirs from the water. Without these minerals, they will suffer from severe mineral deficiencies and possibly die.
The second option is more inconvenient, but I do know someone who uses this option. For this option, you would take several buckets and drive to a friend’s house. The friend must have a different water supply than you. Fill the buckets and take them back to your house to dechlorinate and use.
The final option is to install a reverse osmosis filter which filters out most contaminants. The only downside to these is the cost and the need for a remineralizer. Reverse osmosis systems remove almost all minerals from the water, so you must remineralize them. The upside to these is that you control exactly what goes into your water. There are many commercially available remineralizers, most of which are for specific fish, making selection easier.
Flushed Tap Lines
Every now and again, the city has to “flush” the tap lines in order to clean them. The city must give you a notice that they are flushing the tap lines and often recommend boiling your water. During the next few days, the water will be unsafe for both you and your fish. You should avoid water changes and drinking straight tap water during these times.
When flushing tap lines, the lines are flooded with excess cleaners, often chlorine. You can boil excess chlorine out, hence the notice to boil water. It takes approximately twenty to thirty minutes to boil chlorine out of water when in normal amounts.
Chlorine is not the only reason the water is unsafe. Flushing cleans the tap lines and gets rid of mineral deposits. These deposits build up on the insides of pipes and can reduce the water flow. The only problem with getting rid of them is that they have to go somewhere. These mineral deposits can end up in residential areas and are extremely harmful to aquatic life.
Well water is a bit of a different story. Wells very rarely have ammonia, but they often have nitrates. Nitrates are another by-product of cycling a tank and are harmful to fish when over 20ppm. Unlike ammonia, mammals do not process nitrates as well, so excess nitrates can also be harmful to humans.
The water also tends to be extremely hard from mineral deposits. Since wells sit underground, the mineral deposits around them seep into the water. This means those with wells may only be able to keep hard water fish, such as livebearers. Fish such as bettas may not be able to survive in the hard water as they are soft water fish.
Houses supplied by wells are few and far between and are often somewhere in the country. If the house is away from major cities and pollutants, rainwater can be collected in a water butt. Rainwater is like RO water because it contains very little minerals. You can mix rainwater with the well water or remineralize it for use in aquariums.