What are we doing wrong?  Do we have too many other fish?  Do we need to feed more often?  Why is it only the females are dying and our males are thriving?  Help.

Christopher:
Wow!  Well, the demise of two fish in this short a period of time is definitely reason to evaluate your setup.  You don't mention anything about your filtration or water quality, so my first comment would be to check your PH, toxic ammonia, and nitrite levels.  I would venture to guess that at least one of these would be off.  Why?  Well, you have a LOT of fish in this tank.  Including the three seahorses, I count 10 fish in 35 gallons of water!  Unless you have some serious filtration, this is far too many fish for this size setup, especially for seahorses.

Next, you are feeding your horses twice a day.  This could be good or bad, depending on what you are feeding them.  If they are getting foods like brine shrimp and ghost shrimp, twice a day is necessary.  However, with brine shrimp, it is possible to starve a seahorse to death that is actually eating, due to their lack of nutritional content.  If you are feeding mysis shrimp such as Piscine Energetics' frozen mysis, then twice a day can actually be bad, because the mysis contains high quantities of fats called HUFAs.  Overfeeding can lead to liver problems as the organ is increasingly taxed in order to deal with the overabundance of fat.  It is common to feed mysis once a day and only six days a week to allow the fish to process the nutrients.

Finally, let's look at those fish.  There are too many in there for starters, but my main concern is the presence of the Yellow Tang and that dottyback.  Both of these fish are very aggressive and have no business in a seahorse tank.  This makes me think that you may have lost those two horses to stress from being sniped at by the dottyback, or being slammed by the tang.  I have actually seen Yellow Tangs swat seahorses with their "scalpels", knocking them against the glass of the tank, and leaving severe wounds!

As for why only the females died, I have no answer to that, other than perhaps coincidence.

In summary, check those water parameters and rectify any problems, move at least that tang and that dottyback, and monitor what you are feeding and how much.

Question:
Two of my new seahorses were jet black when I got them and now they have turned yellowish orange.  Is this something to worry about?

Christopher:
The coloration of seahorses is contingent upon many things.  Foremost among these factors are things like genetics, surroundings, health, and happiness (based on stress).  Although this issue is highly complex, and can get very scientific, let's look at some basics in this issue, and we can address more profound matters of coloration later on.

Generally, a fish that is more colorful is doing well - healthy and happy.  However, the opposite, drab, dull colors, can be indicators of problems.  That said, let's look more closely at of each of these three elements, starting with health.

The first thought on your mind when these color changes happen should be, "what is wrong?"  This symptom of lackluster coloration can be your seahorse's way of telling you that there is something definitely amiss.  Ammonia or nitrite poisoning, bacterial/fungal/parasite infections, and nutritional deficiencies are common causes of this condition.  Assuming that your water quality checks out, and there are no indications of infection, the next step is to assess the quantity and quality of food the fish are eating.  If the seahorses are not eating enough food or the food lacks ample fat and protein, this can lead to nutritional deficiencies that can be fatal.  Muscle tissues can waste away from lack of protein, and this includes the heart.  Bone density can suffer, and organ functions can become impaired without certain minerals.  Seahorses, as with many fish, require certain specific nutritional element in order to maintain their vivid colors.  Sadly, in the home aquarium, it is quite common for them to lack these components in their diet.  Be sure your seahorses are getting quality foods, filled with adequate amounts of HUFAs (Highly Unsaturated Fatty Acids), protein, and plant and animal pigments.  Mimicking the natural diet of the seahorse, which is essentially grass and mysis shrimp, can provide these.  Remember, brine shrimp are not an adequate food source!

Second, happiness is indicated primarily as a change in coloration.  Drab colors are excellent indicators of too much stress, declining water quality, and inadequate feeding methods, among other things.  Seahorses that hide and change to these dull colors are generally experiencing some sort of dissatisfaction, which should be rectified as soon as possible.  A seahorse in this state will slowly waste away and eventually die, so examine things such as how often you invade the tank, how much traffic there is around the tank or if there is someone/something banging on the tank or otherwise molesting it.  Check your water chemistry for elevated toxic ammonia, nitrites, and phosphates, as well as swings in specific gravity, temperature, or pH.  On the other hand, keeping you horses happy and stress-free can result in more diverse and vivid colors.  Note the use of the word can as a happy seahorse is not necessarily a colorful one, but an unhappy seahorse is almost always lackluster in color.

Lastly, in a drably decorated tank, that is a tank with no live rock or live rock lacking ample coralline algae growth, and other colorful co-habitants such as corals, sponges, and algae, seahorses will tend to take on dull shades of brown and beige.  This is normal behavior, but can mask the coloration as a symptom of something more serious.  On the other hand, in a colorful tank, your seahorses may exhibit colors that are just incredible... lavenders, reds, oranges, yellows, greens, and many other stunning shades.  You can also provide these colors through more artificial means.  Brightly colors strands of nylon rope used as hitching posts can add great color, and I have also heard of people using backdrops or artificial decorations to add color.

So, when you see your horses change their clothes to these less interesting hues, think seriously about these factors, see if there isn't something amiss, and if there is take the cue and resolve it.