Humblefish
Dr. Fish
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Internal Problems (updated 2-24-23)
For simplicity’s sake, there are 6 basic problems a marine fish can experience on the inside:
) I find this to be impractical for the casual hobbyist, and that my "shotgun approach" to food soaking dewormers generally works.
Final Thoughts – Due to the resilience of these critters, it is recommended to treat (or food soak) for a minimum of 2 weeks. However, it is not uncommon for symptoms to persist for 3-4 weeks. Just like with any other disease, you will eventually run up against a strain which seems resistant to the preferred treatment. In which case, you should seek out an alternative medication. (e.g. Praziquantel only treats trematodes & cestodes. So, persistent symptoms of intestinal worms could mean that your fish has nematodes. Which only fenbendazole, levamisole or piperazine treats!)
Video learning:
For simplicity’s sake, there are 6 basic problems a marine fish can experience on the inside:
- Intestinal worms*
Symptoms: White stringy feces, pinched stomach, fish has faded coloration, unexplained weight loss i.e. fish eats heartily but still seems to be losing weight.
Treatment of choice: Fenbendazole (eliminates trematodes, cestodes and nematodes)
Alternative treatments: Praziquantel (trematodes & cestodes), Levamisole (nematodes only), Piperazine (nematodes only)
More info: Prazi resistant intestinal worms? (nematodes)
- Internal parasites (flagellates)*
Symptoms: White stringy feces, pinched stomach, fish has faded coloration, unexplained weight loss i.e. fish eats heartily but still seems to be losing weight. Flagellates are more virulent than worms, and thus can kill faster.
Treatment of choice: Metronidazole
Alternative treatments: Albendazole, Flubendazole and Mebendazole all show promise.
More info: More treatment options for internal parasites
* Internal parasites vs. intestinal worms: Since these can be difficult to distinguish due to near identical symptoms, it is best to always treat for both. You can food soak different medications on alternate feedings; or API General Cure and Fritz Paracleanse both contain praziquantel + metronidazole in a single medication.
- Internal infections (bacteria)
Symptoms: Internal redness, bloating, lumps or swollen areas on the body. Also, poor water quality can cause/exacerbate an internal infection.
Treatment of choice: Metronidazole combined with Neomycin Sulfate (e.g. Seachem Neoplex) in a medicated fish food slurry.
Alternative treatment: Seachem Focus claims to be an "antibacterial polymer for internal infections of fish." The active ingredient found therein is nitrofurantoin.
More info: Bacterial Infections and Antibiotics.
- Swim bladder disorder
Symptoms: Fish swims vertically with the tail up. Basically, the back half of the fish will seem more buoyant than the front half, and the fish will swim in a way to compensate for that. The fish may also stay near the surface of the water (or even float), unable to swim downward. A protrusion (gas bubble) may be visible near the swim bladder area. In most cases, swim bladder disorders are caused by improper decompression of deep water species.
Treatment: If a gas bubble is present, you can lance the air out using a 30 gauge insulin syringe (READ THIS).
For a swim bladder infection: (a) 30 minute Methylene Blue bath or dose MB at half strength in a quarantine tank. (b) Another quarantine tank option is to dose Metronidazole in conjunction with Neomycin (e.g. Seachem Neoplex). You can food soak this combination as well.
- Spinal injury
Symptoms: Fish swims vertically with the tail down. Sometimes the fish just lays on the bottom of the tank; sometimes it swims in a swirling motion. Most believe spinal injuries are caused when a fish jumps and hits a hard object (or swims/rams into one.) Alternative theories include internal flagellates and/or harmful bacteria migrating to the spinal canal, or even an unknown neurological condition. Wrasses seem most prone to spinal injuries, especially fairy & flasher wrasses.
Treatment: The injury can heal if the damage is minor. Sadly, this is most often not the case.
- Fish constipation
Symptoms: Bloated stomach, obvious anal obstruction, rectal prolapse, erratic swimming behavior. The fish will sometimes stay near the surface of the water, swimming in circles.
Treatment options:
(a) Feed peeled boiled green peas (high in fiber)
(b) Sprinkle a pinch of Epsom salt into the feed (laxative)
(c) Dose Kanamycin (Seachem Kanaplex) in a Quarantine Tank (diarrhea is a known side effect of kanamycin)
- 1 tbsp food (preferably frozen food or pellets)
- 1 scoop (~ 1/8 teaspoon) of medication
- 1-2 scoops of Seachem Focus (binder) OR unflavored gelatin or agar are other binding agents that can be used.
- A pinch of Epsom salt to help expel dead worms/parasites
- Several drops of saltwater or fish vitamins to wet everything down
- Stir until a medicated food slurry has been achieved
- Feed after soaking for 30 mins
- Refrigerate or freeze any leftovers for future use
- Feed daily for 2-3 weeks
) I find this to be impractical for the casual hobbyist, and that my "shotgun approach" to food soaking dewormers generally works. Final Thoughts – Due to the resilience of these critters, it is recommended to treat (or food soak) for a minimum of 2 weeks. However, it is not uncommon for symptoms to persist for 3-4 weeks. Just like with any other disease, you will eventually run up against a strain which seems resistant to the preferred treatment. In which case, you should seek out an alternative medication. (e.g. Praziquantel only treats trematodes & cestodes. So, persistent symptoms of intestinal worms could mean that your fish has nematodes. Which only fenbendazole, levamisole or piperazine treats!)
Video learning:
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