How Do You Medicate Fish?



This usually involves the application of a paste/gel onto an external lesion (e.g. applying dilute Betadine over a bacterial skin infection).

PARENTERAL (i.e. via injection)

Intramuscular (IM)

This is the most commonly used method for antibiotic injection. Aim for the muscle block just ventral and caudal to the dorsal fin. The needle should be positioned between the scales and aimed to come in from a caudo-rostral angle. Inject slowly to prevent reflux. The medication is rapidly dispersed by the rich blood supply. This technique is recommended for gravid females and not recommended for small fish and fish with little muscle bulk. The disadvantage of this method is that the injection site may discolour (aim for dark coloured areas on the fish so that melanisation will not show).

Intraperitoneal (IP)

Place the fish on its side or on its back to allow the peritoneal organs to gravitate away from the body wall. Insert needle into this space at a shallow angle to avoid penetrating the internal organs. This is a common route of administrating vaccines as it is done on small fish and will not harm the flesh. It is also good for administrating “painful” medications such as enrofloxacin. The disadvantages of this method are:

• damaging the peritoneal organs or,

• if injected into the ovary, the drug will not redistribute to the rest of the body, and

• if injected into the intestinal lumen, the drug will be excreted.

Intravenous (IV)

Fish must be anaesthetised. Insert the needle midline and at 90 to 45 degrees, needle pointing towards the front, just caudal to the ventral fin. Stop just short of the spine. This technique is used more commonly for drawing blood than for administering drugs.


Per os

This is a common delivery method for antibiotics on large farms for ease of medicating large numbers of fish and also minimises handling stress. However, the delivery of the correct doses to each individual fish is difficult (sick fish are usually inappetent and it is these that should actually be receiving the medication). Medication is either sprayed onto the food, impregnated into the food, or prepared with food coated with medicated gelatin, agar or oil. Depending on the drug, this medicated food may sometimes be less palatable. It is thus recommended to reduce the amount of food fed per day by 25-50%.

Gastric intubation

If fish are not eating, they can be anaesthetized and force-fed via a stomach tube. Use a 3mm outer diameter catheter and a 5ml syringe (for larger fish, use a 6mm outer diameter with a 20ml syringe). Administer 1.0-1.15 ml/kg body weight. Due to the high pressure needed to deliver the suspension, the tube may need to be glued to the syringe with cyanoacrylate (e.g. super glue).



This is useful for external parasitic infections and involves using relatively high concentrations of drugs dissolved in the water of a treatment tank. Fish are held in nets and briefly immersed in the treatment solution and then placed into a hospital/quarantine tank. This is often used for new arrivals. Make sure dips are refreshed regularly.


This is a variation of the ‘dip’ treatment. It uses lower drug concentration and involves allowing the sick fish to swim in the medicated water for a period ranging between 2-60 minutes. These are useful for external infections including protozoal, bacterial and fungal. Commercially, this method is used for vaccinating fish against bacterial infection.

Prolonged immersion / permanent bath

This is yet another variation of medicated water where very low concentrations of the drug is used, but the length of exposure is increased. This is particularly useful if the parasites have stages in their lifecycle when they are refractory to treatment (e.g. white spot disease) – the longer exposure time in the medicated water will increase the chances of killing the parasites when they reach the susceptible stage. This method is also used to reduce osmoregulatory stress, when 2-5mg/L of salt (sodium chloride) is added, in conjunction with other forms of treatment. It is also the most frequently used method where client compliance may be low as it is the easiest option.

How Do You Properly Maintain a Pet Piranha Tank?

Owning a pet piranha is not just about setting up their home once and then forgetting about it. There is a little bit more involved in maintaining a piranha tank and I’m hoping that this article will provide you with the necessary steps and guidance.

Although it isn’t extremely complicated, maintaining an aquarium does require a little bit of effort on your part. Just feeding your pet fish and watching them swim isn’t going to be enough. It is important to monitor the state of the aquarium and the state of your piranhas on a daily/weekly basis. Below is a list of steps that will help you properly maintain your pet piranha’s home:

1. Check the water chemistry on a weekly basis. At a minimum, make sure the following levels are maintained:

Temperature Range – 73°F – 81°F
pH Range – 5.5 – 7.0
Hardness – 15° – 20°

2. Keep an eye on algae.

Algae is the green mossy substance you sometimes see on the aquarium walls and decorations. One way to prevent algae is by introducing a few algae eaters to your tank. For example, plecos or snails. An alternative is to scrape the algae once it develops, using a simple algae scraper. (In fact, scraping the walls of your aquarium before the algae appears is also a good step.)

3. Clean your filter components.

From time to time you will have to clean the filter and its components. However, it is important to note that not all components should be cleaned at the same time. Over time, bacteria builds up on the filter components and some bacteria is essential for your piranha’s health. Most aquarists will recommend cleaning one component per week.

4. General clean-up and water changes.

Replace approximately 20% of the water every week or so. You can do this by using an aquarium vacuum, which allows you to suck debris lying around on the gravel and ornaments while removing some of the water at the same time. Once approximately 20% of the water has been removed, replace it with fresh tap water. Things to note:

a. Use a bucket specifically dedicated for your aquarium (i.e.: do not use any household bucket that you may have used for cleaning the house. Left over chemicals may harm your piranhas.)

b. Make sure the new water is the same temperature that is already in your aquarium to avoid shocking and stressing your piranhas.

c. Add the new water slowly (i.e.: 4-5 cups every 15 minutes or so).

This may seem complicated at first, however the more you do it, the faster and easier it becomes!

Please make sure you visit my Web site for more information about piranhas and aquarium maintenance!

The Pacu Piranha? Or Merely Piranha’s Ugly Cousin?

The pacu is often mistaken with the piranha because they share similar features such as color, general shape, etc. However, they are not the same. This article will begin with the similarities/differences of each.


* They are from the Serrasalminae subfamily, which essentially makes them cousins.
* They are both freshwater fish
* They are usually found in the major river basins in South America.
* Both can be kept as pets in home aquariums


1. Eating Habits

Piranhas are carnivores and for the most part they stick to small animals that live in or close to water. They also snack on snails and plant life. Pacus are mostly herbivores and normally stick to vegetables, seeds and nuts that fall in the water. They also eat other fish when the mood strikes them.

2. The Teeth

Piranhas have very pointed razor-sharp teeth which allow them to shred almost anything within seconds. Many also have an underbite. Pacus on the other hand have straighter teeth which are square shaped. If fact, they look sort of human and are extremely powerful. Their underbite is not as severe as the piranha, and in some cases they may even have an overbite.

3. Size

Pacus are much larger than piranhas once they are fully grown. Adult pacus can reach up to 3 feet and weigh up to 50 pounds in the wild. Wild piranhas usually grow to 12-15 inches and usually weigh no more than 7-8 pounds.

Pacus as Pets?

Owning a pacu as a pet is possible however you must keep in mind that the biggest challenge will be its size. Contrary to what certain people say, pacus are not limited by the tank size. They will grow to whatever size they are destined to grow to. Aquarium pacus have been known to reach up to 2-3 feet and 35-45 pounds. If you decide to bring one home as a pet and it becomes unmanageable, do NOT throw it in the nearest river or lake. Instead, visit your local pet store to see if there is anything else that can be done. They may be able to take it off your hands or at least point you to someone who might want to take it on.

The other thing to keep in mind is the cost of aquarium equipment. Pacus need a lot of filtration power to keep their homes clean. Some pacu owners often have 2, even 3 filtration systems to handle the work load.

Please make sure you visit my Web site for more information about piranhas!

Quarantining Fish

Quarantine tanks are recommended for all aquariums. If you plan to add new fish to your tank after the whole tank was complete, you should consider getting a quarantine tank. It is also considered to be a hospital tank because it is used to treat diseased fish. A quarantine tank is basically a place where the fish temporarily lives for the one of the two reasons listed above. Normally a ten to twenty gallon tank can be used as a quarantine tank.

When adding a new fish to the tank, it is very important to isolate the fish before adding it to the main aquarium. A newly bought fish need to be examined carefully. You want to make sure that the fish is not diseased or, in any way, unhealthy; make sure that it is behaving the way it is supposed to. If you add the fish to the tank right away without ensuring its health, it may spread to the other fish in your tank and possibly wipe out your entire tank population. It is better to be safe. The fish should stay in the quarantine tank for at least two weeks. It is considered a need for saltwater aquarium keepers. If you have a saltwater aquarium, not only will you need to quarantine the fish, but you should also quarantine corals. Corals can introduce different pests and diseases to your aquarium.

Quarantine tanks are more of a hospital tank for saltwater aquariums rather than freshwater aquariums because freshwater fish generally do not break out in disease as readily. However, for both, in order for the diseased fish to not affect the other fish in the aquarium, and invertebrates for saltwater aquariums, quarantining them is a must. When treating diseased fish, the medicine used can affect the whole tank. However, when the diseased fish is being quarantined, the medicine will benefit the diseased one without negatively affect the healthy ones.

In order to set up a quarantine tank, you will need a filter, a heater, an air stone, some sort of hiding place for the fish, test kits for pH, ammonia, nitrites, and nitrates, a fish net, and water from your main tank. The filter can be a hang on, power filter on the back of the tank. You can also use filter floss, however, without the carbon because then the medication will be removed from the water. A heater is only necessary for a freshwater quarantine tank because the temperature of the water for freshwater fish has to be 72 to 82 degrees Fahrenheit. An air stone is used to provide the fish with more oxygen. For the hiding place, you can simply use some PVC pipes; it is for the fish to hide and relieve stress. The test kits are to keep the pH, ammonia, nitrites, and nitrates level of the water at where it’s supposed to be. When the list says fish net, it has to be a fish net different from the one you use for your main aquarium because you do not want to spread the disease to your healthy fish through the fish net. Finally, water from your main tank. Since that water contains the nutrients and everything appropriate for the fish to live in, it is what you will use for the quarantine tank, too. You will not have to do the process you did when you first started the aquarium.

About Starting a Salt Water/Marine Aquarium

Saltwater aquarium fish are among the loveliest of animals to be found anywhere in the world. Many different saltwater aquarium fish can be housed in your marine tank provided you will know the things they need in regards to care, that include feeding, environment, competitors and space to grow.

Any marine enthusiast strongly believe that setting up a marine tank is difficult hence is selecting the most appropriate saltwater aquarium fish! This is because it’s easy to make mistakes with the kinds of fish you prefer. It’s usually preferable to start your marine tank which has a few hardy and affordable fish. The vast majority of saltwater aquarium fish are collected from nature as an alternative to captive raised so don’t waste that gift by making mistakes that result in the death of your fish.

Damsels absolutely are a great saltwater aquarium fish to start off with. Damsels are hardy little creatures and that can survive in poorer water conditions than many other marine species. They aren’t fussy about their food and won’t cost you the earth. Unfortunately damsels are also quite aggressive. You are able to keep just one or two of these tough saltwater aquarium fish in a tank but don’t try any more than that.

Its best to start with damsels and after that add extra aggressive fish later, If you would like to house saltwater aquarium fish that might be more shy, it is important for you to take your damsels out before adding more timid varieties of saltwater aquarium fish. Blue and yellow damsels are two species that are generally less aggressive compared to others.

Mollies are an alternate starter saltwater aquarium fish. Mollies that are used to salt water allow you to start with cheaper fish while you learn how to make sure the salinity of your tank is correct for more sensitive creatures. Alternatively mollies are raised and bred in captivity this means you won’t get much real experience in keeping them. Make sure you get them used to the tank by allowing saltwater to drip into the bag for approx 6-8 hours. In the event the bag becomes full remove some water. As the tank cycles you may put the fish in the tank.

Clownfish are cousins to damsel fish and are a relatively hardy saltwater aquarium fish. They are not that easy to acclimate to a marine tank, though. They’re also quite territorial but aren’t more likely to be aggressive to other species. They don’t have to have an anemone to survive. Say you do get one consider that they would need water that’s very clean and superior quality lighting.

Blennies or Gobies are fairly hardy and small and shouldn’t really become a problem for the other saltwater aquarium fish inside the tank. They’re character fish but they are little and so might get lost in very big tanks with bigger saltwater aquarium fish. They’re really a good choice that will help control algae however if you have a fish only tank they may not be easy to keep fed.

Tangs undoubtedly are a hardy saltwater aquarium fish which could be a little bit sensitive and have an inclination to contract marine ich (also know as “White Spot”). They eat algae so as soon as you grow some you could possibly make an attempt to introduce some tangs.

Triggerfish or Lionfish are an ideal saltwater aquarium fish to create a tank that might eventually contain large aggressive fish. However they can be costly if you make mistakes. It might be a good idea to ‘practice’ on fish that are generally both cheaper and easier. You need to provide them a large amount of shell fish as well as other sea creatures to keep them healthy.

Angels and butterflies are extremely sensitive and difficult saltwater aquarium fish to keep. They should get special diets much of the time so they typically are not that easy to care for within a tank. The same goes for Batfish.

As you gain more experience in keeping conditions in the tank stable you have the option to put a few other varieties of fish. Select from Hawkfishes, Grammas, Dottybacks, Basslets and wrasses. But remember to learn how you can take care of them properly because some are not as easy as others. However they are a much easier bet that angels and butterflies.

So which saltwater aquarium fish should beginners avoid? You should not attempt angelfish, butterfly fish, Pipefish, seahorses, long-nosed Filefish, blue ribbon eels, Stonefish, and Moorish Idols as well as mandarin fish until you really know what you are doing.

And what about invertebrates? Contrary to popular belief invertebrates are well suited for mini or micro-reef tanks. Many invertebrates do good in non-reef tanks. For the novice aquarist the hardy species are best. Some of the more common are shrimps like the cleaner shrimp, blood shrimp or peppermint shrimp and coral banded shrimp. As is the case with saltwater aquarium fish, stick to the hardier shrimps to start with.

Anemone crabs are another option you can possibly try along with saltwater aquarium fish. And why don’t you add some sea urchins and starfish which are very well suited to beginners with a couple of month’s experience? They differ in size, shape and color and many are poisonous so be mindful! Sea urchins and starfish eat detritus and algae along with other small bits of food which means they’ll help in keeping your tank clean and your saltwater aquarium fish healthy.

Anemones aren’t really suited for beginners. They are in need of special lighting and top-notch water conditions therefore if you can’t foot the bill for the lights refrain from it or you’ll live to be disappointed. Invertebrates you ought to avoid include tridacna clams, flame scallops, Octopi, Nudibranchs, or any hard or soft coral and sea squirts. Much like the saltwater aquarium fish listed previously these invertebrates have special feeding and living requirements.

When you select saltwater aquarium fish, you have to take into account that they are a bit more expensive than the freshwater varieties. Because of this you ought to be very careful with them and try to keep them alive. When fish are captured and moved from the store to your current home they actually are liable to get stressed, especially since the majority of of them have been taken from the ocean mere days ago. So be sure you can properly care for your new friends before you bring them home!