Weasel gave the best advice here... The mix of fish in this tank is horribly mismatched, and with the warmer temps, the goldfish are likely to experience many health problems. A goldfish's organs are not equipped to handle warmer water temps over a long period of time, and if it gets too warm, the damage can be fatal. A little bit at a time, their systems will shut down until the fish die. Also, warm water contains less oxygen, and goldfish are high consumers of oxygen.
How much decoration is in this tank? By silver shark, are you referring to bala sharks? http://badmanstropicalfish.com/richards/bala.jpeg
If this is what you added, be aware that these grow to 14 inches on average, and 4 of them in a 95 gallon tank won't last for more than about a year.
Black widows.... I'm not familiar with this common name... are these black skirt tetras? http://z.about.com/d/freshaquarium/1/0/m/G/fw0124.jpg
Can you post a picture of the tank and the fish? Knowing the specific species of fish, and also your water params (ammonia, nitrite, nitrate, and pH) would also help a lot. There are a number of possible causes for the way your fish have been acting, but you haven't posted nearly enough information for anyone to be of real help, other than to point out that the goldfish need cold water (63 - 65 degrees fahrenheit would be the warmest I would suggest for them). How long has this tank been set up? How often are you feeding the fish and what foods are you offering them? How often are you doing water changes?