Brown Spots

There we go, thanks petco employees
Anyway, hows the temp of the tank? plants need a low temp to survive, under 80 farenheit is best for plants
My aquascaped zebra pleco tank has a co2 generator and a fan to control the temp

 

It is perfectly true that you do not need to be adding diffused CO2, depending a bit on the plant species and other factors like lighting intensity and nutrients.  However, nutrients in general may be lacking, and your observation of no fish providing some of these is accurate.  I have a 20g tank that I use only to quarantine new fish acquisitions, and it is planted.  It can sit without fish for months, but I do notice an improvement in the plants' appearance when fish are present.  Some of this is natural CO2, but more is the nitrogen (ammonia/ammonium) which plants need.  Some will occur from organics in the substrate, but the main source is obviously fish.
 
Having said that, it is still possible to have decent plants, so now we must look into the lighting.  If you could detail your light--including type, wattage, duration, spectrum...anything you can--it will help.
 
Another factor is that plants do take a time to adjust to differing parameters and environments, over usually a period of a couple weeks or more.
 
The GH of your source water is another factor, as this is the prime source of the "hard" minerals like calcium, magnesium, and a few others.  If you could give me the GH (and pH while we're at it).  Temperature is fine at mid to high 70's.
 
Last, what plant species do you have?  The large plant in the photo appears to be a sword, Echinodorus species, maybe E. osiris?  It is in bad shape, no denying, but we should be able to save it.  However, this is a genus of plants that are quite heavy feeders, and adding a comprehensive liquid plant fertilizer is almost a necessity.
 
Byron.

 

Byron is right, light is also something you have to look into and as charlie said, fertilizer is really important. Light and fertilizer is what the the crispus species need most take a look at this: http/www.aquaticplantcentral.com/forumapc/plantfinder/details.php?id=87

 

I would question that that plant is Aponogeton crispus.  I had thought possibly an Aponogeton initially, but I can see no sign of the tuber (bulb) at the base, plus the wavy edge of the leaves is not crispus, and third the leaf veining is Echinodorus not Aponogeton.  Having said that, the plant is in rough shape...but I still doubt the genus.
 
What do you mean by "getting the ammonia under control?"  This may be significant, as ammonia is highly toxic to plants as well as fish, depending upon the level.
 
Light...by "regular bulbs," do you mean ordinary household incandescent bulbs?  Or CFL (the spiral compact fluorescent)?  And to put this in perspective, what is the tank size, the volume and dimensions?  "Bright" light to you or me may not be bright to plants.  Of it may be too bright, this can kill plants too.
 
To your tap water, do you have any idea if it is hard, moderately hard, soft, very soft?  I'm really not thinking this is the issue, but it is one factor that may or may not be significant here.
 
Byron.

 

 
Getting the GH and KH values from your water company won't help much.  Water companies may get their water from multiple source and the water hardness may change from month to month. Also Keep in mind the aquarium is an enclosed environment.  The water chemistry in the aquarium will change as the plant removes minerals from the water.  You really should get a test kit that will measure Hardness (GH) and total Alkalinity (KH).  Tetra Easy strips will measure GH, KH, PH,and nitrogen (Nitrate / Nitrite)
 
 elements such as calcium, magnesium, iron, zinc, boron, sulfur, manganese, and molybdenum are known as micro nutrients because the plants don't need a lot  of these and becasue there is not much dissolved in the water.  Micro nutrients are among the first to be depleted from the water.  another class of elements are known as Macro nutrients such as potassium, phosphorous, and nitrogen.   Plants usually need a lot of these nutrients and once you have fish you should have enough of these to keep your plant alive.   
 
To restore your plant to health you should use a fertilizer with macro and micro nutrients such as Seachem flourish.   Once you stock you can probably reduce or maybe elliminate the amount of fertilizer needed.   I personally use Aqueon micro fertilizer and have been recently adding Potassium Nitrate due to algae issues I have. When Using micro nutrients only I typically never see Ammonia or nitrite.   Nitrates occasionally show up but only at very low levels

 

 
OK, that is an Aponogeton then.  These plants (most species) require a rest period when they lose their leaves.  Just leave the bulb/roots, and new leaves will appear after a couple months.  I have Aponogeton in my 90g and this is a regular annual cycle.  They do need nutrients however, as what is in the bulb can be readily used up.  I have found that root tabs are ideal, one placed next to the bulb/roots, replaced according to directions depending which brand.  I am using Seachem's Flourish Tabs, they are replaced every 3 months.  Also, a liquid fertilizer would probably be a good idea, such as Flourish Comprehensive Supplement [look for this exact name, they make several products under the "Flourish"], and it is concentrated and contains all nutrients necessary.  Aquatic plants take up nutrients via the roots and leaves, so these two provide what is necessary.

 

MOST plants need low temps. Rotala Wallichii actually prefers temps above 80. It is actually going to be my own go-to species for my L-46 breeding tank.