Bob replies...

Hi Sergio,

Thanks for your letter, and see several areas that need attention. Let's first begin with HLLE and even though you already have some info on this malady, I want to use your letter and revised answer in a future issue of FAMA, as it depicts several areas that when combined, can lead to poor water quality and possibly initiate this malady.

As you already know from the above mentioned article, this malady often appears as a pitted area on the face and/or along the lateral line of the fish, the cause of which has generated much conjecture in the aquarium world. In fact, your Regal/Blue/Hippo (Paracanthurus hepatus) Tang is also highly susceptible, as I've seen this malady on quite a few of them over the past years. And many reasons for this malady have been put forth, e.g., vitamin deficiencies, stray electrical current or free electromagnetic fields, exposure to heavy metals, protozoan organisms, poor water quality, stress, use of activated carbon, certain medications, and even various viral and bacterial infections have been cited. And with so many thought-to-be causes, any one or combination of them could be the actual source of the problem.

Nevertheless, I'm of the opinion that poor or inadequate diet combined with stress and poor water quality (in that order) remains the leading cause. In fact, in my opinion, HLLE could be considered comparable to rickets or beriberi in humans, and that poor water quality and stress no doubt irritates a vitamin/mineral deficiency and the deteriorated areas on the fish body then become a haven for bacteria and viral infections.

And the reason why I feel that poor or inadequate diet is the cause is that I've helped cure a Purple Tang that had come into a local aquarium shop riddled from head to tail, or what was left of the tail, with HLLE. That fish was given to a local friend who placed it in his 100-gallon aquarium that contained some lionfish and lots of good hiding places. The water was of excellent quality, and the Tang was fed flake food soaked in an all-natural multi-vitamin solution (available from local health shops) and was also given the excess macroalgae (Caulerpa mexicana and C. prolifera) from one of my aquariums.

The flake was fed as often as possible in the beginning, sometimes as many as ten to fifteen times a day. Only a small pinch of treated flake was dropped in the aquarium, never any more than the fish would eat in a minute or two. Within a few months the fish was almost fully recovered and was beginning to look like it just came from the ocean! About a year later the above remedy was suggested to a fellow hobbyist in England, who was having a severe HLLE problem with one of his Angelfish (in fact, same species as yours). After trying the recommendation for a few months, he wrote back saying the fish was returning to normal.

Keep in mind your Queen Angelfish is a browser, no different than the cow in the meadow, and likes to munch throughout the day on tasty morsels. With micro and macroalgae containing a wide variety of trace elements and vitamins, it becomes the perfect in-between major mealtime snack, which should consist of some meaty foods, e.g., containing mysis, krill, brine shrimp, and possibly some sponge material that have nutritional additives applied to them, e.g., American Marine Selcon. And if time allows, try the treated flake, such as 'Spirulina,' several times a day as mentioned above. Also, try some broccoli, which contains Vitamin A, C, E, and some iodine. It can be fed occasionally, fresh or blanched. Also, since fish exposed to natural sunlight don't seem to be affected by this malady, possibly due to the fact that Vitamin D synthesis requires exposure to sunlight, some foodstuffs containing a Vitamin D supplement may also help.

As for keeping Caulerpa healthy, it first helps to understand some general facts about this popular alga, e.g., it can assume different morphological forms depending upon their environment. Variations in temperature, nutrient level, salinity, current, light, and even substrate can have a marked effect on its growth form. In fact, members of the same species can look completely different depending on where they come from. Root-like holdfasts grow along their rhizomes and attach themselves to gravel, rock, and even coral animals. The main purpose of these growths is to anchor the plant to a substrate surface, yet some uptake of nutrients is thought possible. However, the majority of nutrient uptake is through the fron/leaf structure.

Caulerpa are coenocytes, i.e., a multinucleate cytoplasm appearing as many interconnected segments. The proper way to break off a section of the plant is to crush the thallus (stem), not make a clean cut, such as with a scissors. Clean cuts can lead to internal damage and quickly cause a section or the specimen itself to disintegrate. Beside disintegration from physical abuse, cellophaning, i.e., becoming transparent can be caused by sexual reproduction. When this occurs the Caulerpa leaf will first become blotchy. Soon after blotchiness appears, hair-like discharge tubes called 'papillae' will form along the edges of the leaves and discharge gametes and some remaining cytoplasm.

There are some thoughts as to why Caulerpa enter the sexual cycle. Some think it is brought about by salinity changes. Some think it may simply be a biological clock. Others think it may be brought about by a lack of nutrients, e.g., carbon dioxide, nitrate, iron or that of excess organic material. No matter what the cause, when Caulerpa begins to cellophane, those leaves should be removed before disintegrating altogether. If allowed to continue, the plant's nutrients will be released into the aquarium, reducing overall bulk water quality.

Whether your Caulerpa deterioration was caused by a major salinity change from the tank where it was purchased or that may have initiated the biological clock, it did increase the nutrient load in your tank. Did this and the adding of activated carbon cause the angelfish to develop HLLE - I doubt it. If anything, it may have aggravated a developing problem area. And improved water quality and feeding is highly recommended to turn that situation around.

Furthermore, Caulerpa, as most algae, do better under regular daylight fluorescent lamps than under more expensive blue spectrum lamps such as 6500K or 10K lamps. Algae prefer longer wavelength light, such as the red band wavelength. Higher Kelvin rated lamps have more blue-green spectrum, which algae do not find as useful as the red band. Caulerpa also prefers what could be termed average water conditions, i.e., where nutrients such as nitrogen-laden compounds such as ammonium, nitrite, and nitrate are available, and of course phosphate to provide the energy for growth are also readily available. It may be that an iron additive could also help maintain a more lush growth of macroalgae. When such growths exist, they should be maintained by simply harvesting the oldest one-third of growth as necessary. And even though there are about seventy different species of Caulerpa, stay with the two mentioned above as they are the most 'tasty' when it comes to most of the animals we keep in our aquaria.

Your water appears to have all the nutrients needed (except iron), and as a fish-only aquarium, would not be overly concerned with your parameters except where 'ammonia' is concerned. If what you show in your letter were correct, this would indicate the biological processes are overwhelmed, and not keeping a balanced approach with the incoming food and generated waste expelled into the aquarium. And if correct, this ammonia content could be the 'stress' factor the angelfish is battling each day in your aquarium!

To sum it up, yes, maintaining a healthy growth of these forms of Caulerpa and feeding some of the excess to your Tang and Angelfish will greatly help maintain them in a healthy fashion and also promote better water quality. Keep in mind most fish require a wide range of foodstuffs and that it be properly administered to fit their individual diet needs. Add to this a 10 - 15% water change on a monthly schedule, and things should markedly improve. And furthermore, your nitrate level for a fish only tank is not overly high, especially in a system that uses a wet/dry. If you do not already have a protein skimmer, suggest getting a quality unit as that will help reduce nitrate somewhat, and at the same time increase dissolved oxygen, helping to promote a healthier environment for everything in your aquarium.

Hope this helps,

Bob