Digenean Trematodes

[Mr.Reefer]

These internal worm infections are actually quite common in the wild. Most fish appear to be oblivious to the presence of these parasites unless they are in an otherwise weakened condition. It is surprising how many of these parasites a fish can host and still appear to be healthy. It has been reported that Trematodes, Metacercaria, or Nematodes are found in up to 85 percent of marine fish examined. At the risk of spoiling someone's appetite for fish, try soaking a freshwater fish fillet in saltwater or the saltwater fish fillet you are planning on as dinner in freshwater. You may discover that some types of worm infestations are more common than you would like to know about.
Some possible symptoms are as follow:
• Weight loss, even though the fish eats normally in early stages
• Usually only one or two fish seem to be affected
• Loss of appetite in advanced stages
• Fish become listless
• White spots that are most easily seen in clear fins appear to be imbedded in the fin rays
• Dark spots under the skin that do not respond to treatment with Formaldehyde
• Exophthalmos (popeye), or blindness
• Secondary bacterial infections in late stages